Mucin (Muc) expression during pancreatic cancer progression in spontaneous mouse model: potential implications for diagnosis and therapy

Pancreatic cancer (PC) is a lethal malignancy primarily driven by activated Kras mutations and characterized by the deregulation of several genes including mucins. Previous studies on mucins have identified their significant role in both benign and malignant human diseases including PC progression and metastasis. However, the initiation of MUC expression during PC remains unknown because of lack of early stage tumor tissues from PC patients. In the present study, we have evaluated stage specific expression patterns of mucins during mouse PC progression in (KrasG12D;Pdx1-Cre (KC)) murine PC model from pancreatic intraepithelial neoplasia (PanIN) to pancreatic ductal adenocarcinoma (PDAC) by immunohistochemistry and quantitative real-time PCR. In agreement with previous studies on human PC, we observed a progressive increase in the expression of mucins particularly Muc1, Muc4 and Muc5AC in the pancreas of KC (as early as PanIN I) mice with advancement of PanIN lesions and PDAC both at mRNA and protein levels. Additionally, mucin expression correlated with the increased expression of inflammatory cytokines IFN-γ (p?相似文献   

Axed MUC4 (MUC4/X) aggravates pancreatic malignant phenotype by activating integrin-β1/FAK/ERK pathway

Alternative splicing is evolving as an eminent player of oncogenic signaling for tumor development and progression. Mucin 4 (MUC4), a type I membrane-bound mucin, is differentially expressed in pancreatic cancer (PC) and plays a critical role in its progression and metastasis. However, the molecular implications of MUC4 splice variants during disease pathogenesis remain obscure. The present study delineates the pathological and molecular significance of a unique splice variant of MUC4, MUC4/X, which lacks the largest exon 2, along with exon 3. Exon 2 encodes for the highly glycosylated tandem repeat (TR) domain of MUC4 and its absence creates MUC4/X, which is devoid of TR. Expression analysis from PC clinical samples revealed significant upregulation of MUC4/X in PC tissues with most differential expression in poorly differentiated tumors. In vitro studies suggest that overexpression of MUC4/X in wild-type-MUC4 (WT-MUC4) null PC cell lines markedly enhanced PC cell proliferation, invasion, and adhesion to extracellular matrix (ECM) proteins. Furthermore, MUC4/X overexpression leads to an increase in the tumorigenic potential of PC cells in orthotopic transplantation studies. In line with these findings, doxycycline-induced expression of MUC4/X in an endogenous WT-MUC4 expressing PC cell line (Capan-1) also displayed enhanced cell proliferation, invasion, and adhesion to ECM, compared to WT-MUC4 alone, emphasizing its direct involvement in the aggressive behavior of PC cells. Investigation into the molecular mechanism suggested that MUC4/X facilitated PC tumorigenesis via integrin-β1/FAK/ERK signaling pathway. Overall, these findings revealed the novel role of MUC4/X in promoting and sustaining the oncogenic features of PC.     

Mucin 16 is a functional selectin ligand on pancreatic cancer cells

Selectins promote metastasis by mediating specific interactions between selectin ligands on tumor cells and selectin-expressing host cells in the microvasculature. Using affinity chromatography in conjunction with tandem mass spectrometry and bioinformatics tools, we identified mucin 16 (MUC16) as a novel selectin ligand expressed by metastatic pancreatic cancer cells. While up-regulated in many pancreatic cancers, the biological function of sialofucosylated MUC16 has yet to be fully elucidated. To address this, we employed blot rolling and cell-free flow-based adhesion assays using MUC16 immunopurified from pancreatic cancer cells and found that it efficiently binds E- and L- but not P-selectin. The selectin-binding determinants are sialofucosylated structures displayed on O- and N-linked glycans. Silencing MUC16 expression by RNAi markedly reduces pancreatic cancer cell binding to E- and L-selectin under flow. These findings provide a novel integrated perspective on the enhanced metastatic potential associated with MUC16 overexpression and the role of selectins in metastasis.     

MUC4 mucin potentiates pancreatic tumor cell proliferation, survival, and invasive properties and interferes with its interaction to extracellular matrix proteins

MUC4, a transmembrane mucin, is aberrantly expressed in pancreatic adenocarcinomas while remaining undetectable in the normal pancreas. Recent studies have shown that the expression of MUC4 is associated with the progression of pancreatic cancer and is inversely correlated with the prognosis of pancreatic cancer patients. In the present study, we have examined the phenotypic and molecular consequences of MUC4 silencing with an aim of establishing the mechanistic basis for its observed role in the pathogenesis of pancreatic cancer. The silencing of MUC4 expression was achieved by stable expression of a MUC4-specific short hairpin RNA in CD18/HPAF, a highly metastatic pancreatic adenocarcinoma cell line. A significant decrease in MUC4 expression was detected in MUC4-knockdown (CD18/HPAF-siMUC4) cells compared with the parental and scrambled short interfering RNA-transfected (CD18/HPAF-Scr) control cells by immunoblot analysis and immunofluorescence confocal microscopy. Consistent with our previous observation, inhibition of MUC4 expression restrained the pancreatic tumor cell growth and metastasis as shown in an orthotopic mouse model. Our in vitro studies revealed that MUC4-associated increase in tumor cell growth resulted from both the enhanced proliferation and reduced cell death. Furthermore, MUC4 expression was also associated with significantly increased invasiveness (P < or = 0.05) and changes in actin organization. The presence of MUC4 on the cell surface was shown to interfere with the tumor cell-extracellular matrix interactions, in part, by inhibiting the integrin-mediated cell adhesion. An altered expression of growth- and metastasis-associated genes (LI-cadherin, CEACAM6, RAC1, AnnexinA1, thrombomodulin, epiregulin, S100A4, TP53, TP53BP, caspase-2, caspase-3, caspase-7, plakoglobin, and neuregulin-2) was also observed as a consequence of the silencing of MUC4. In conclusion, our study provides experimental evidence that supports the functional significance of MUC4 in pancreatic cancer progression and indicates a novel role for MUC4 in cancer cell signaling.     

Preferential expression of cystein-rich secretory protein-3 (CRISP-3) in chronic pancreatitis

BACKGROUND: Chronic pancreatitis (CP) is a progressive inflammatory process resulting in exocrine and endocrine pancreatic insufficiency in advanced stages. Cysteine-rich secretory protein (CRISP-3) has been identified as a defense-associated molecule with predominant expression in the salivary gland, pancreas and prostate. AIMS: In this study, we investigated CRISP-3 expression in normal pancreatic tissues, chronic pancreatitis tissues, pancreatic cancer tissues and pancreatic cancer cell lines, as well as in other gastrointestinal organs. MATERIALS AND METHODS: 15 normal pancreatic tissues, 14 chronic pancreatitis tissues and 14 pancreatic cancer tissues as well as three pancreatic cancer cell lines were analyzed. Moreover, hepatocellular carcinoma and esophageal, stomach and colon cancers were also analyzed together with the corresponding normal controls. RESULTS: CRISP-3 was expressed at moderate to high levels in chronic pancreatitis tissues and at moderate levels in pancreatic cancer tissues but at low levels in normal pancreatic tissues, and was absent in three pancreatic cancer cell lines. CRISP-3 expression was below the level of detection in all cancerous gastrointestinal tissues and in all normal tissues except 2 of 16 colon tissue samples. CRISP-3 mRNA signals and immunoreactivity were strongly present in the cytoplasm of degenerating acinar cells and in small proliferating ductal cells in CP tissues and CP-like lesions in pancreatic cancer tissues. In contrast, CRISP-3 expression was weak to absent in the cytoplasm of cancer cells as well as in acinar cells and ductal cells in pancreatic cancer tissues and normal pancreatic tissues. CONCLUSION: These results reveal that the distribution of CRISP-3 in gastrointestinal tissues is predominantly in the pancreas. High levels of CRISP-3 in acinar cells dedifferentiating into small proliferating ductal cells in CP and CP-like lesions in pancreatic cancer suggests a role of this molecule in the pathophysiology of CP.     

Mucins in pancreatic cancer: A well‐established but promising family for diagnosis,prognosis and therapy

Mucins are a family of multifunctional glycoproteins that mostly line the surface of epithelial cells in the gastrointestinal tract and exert pivotal roles in gut lubrication and protection. Pancreatic cancer is a lethal disease with poor early diagnosis, limited therapeutic effects, and high numbers of cancer‐related deaths. In this review, we introduce the expression profiles of mucins in the normal pancreas, pancreatic precursor neoplasia and pancreatic cancer. Mucins in the pancreas contribute to biological processes such as the protection, lubrication and moisturization of epithelial tissues. They also participate in the carcinogenesis of pancreatic cancer and are used as diagnostic biomarkers and therapeutic targets. Herein, we discuss the important roles of mucins that lead to the lethality of pancreatic adenocarcinoma, particularly MUC1, MUC4, MUC5AC and MUC16 in disease progression, and present a comprehensive analysis of the clinical application of mucins and their promising roles in cancer treatment to gain a better understanding of the role of mucins in pancreatic cancer.     

CSN5 promotes the invasion and metastasis of pancreatic cancer by stabilization of FOXM1

COP9 signalosome subunit 5 (CSN5) has been involved in the progression of diverse human cancers. MMP2 plays an important role in the metastasis of cancer cells. However, the roles and relationship of in pancreatic cancer (PC) is still unknown. Here, our data shown that both CSN5 and MMP2 were significantly upregulated in PC compared with the corresponding adjacent tissues, where a positive correlation in their expression and associated malignant characteristics were found. Further, silencing of CSN5 expression markedly inhibited PC invasion and metastasis in vitro and in vivo, accompanied by decreased MMP2 expression. Moreover, the anti-metastasis role of CSN5 silence was reversed by MMP2 overexpression, whereas knockdown of MMP2 decreased PC metastasis driven by upregulation of CSN5. Further investigation revealed that CSN5 regulated MMP2 expression via activation of FOXM1 in PC cells. Mechanistically, CSN5 directly bound FOXM1 and decreased its ubiquitination to enhance the protein stability of FOXM1. Taken together, the results indicate that CSN5 can contribute to PC invasion and metastasis through activation of FOXM1/MMP2 axis.     

MUC6 mucin expression inhibits tumor cell invasion

The MUC6 mucin has a critical protective function in the normal stomach, pancreas and duodenum and is aberrantly expressed during the progression of some gastrointestinal cancers. Our aim was to determine whether MUC6 contributes to the etiology or progression of pancreatic cancer and elucidate the molecular basis of its involvement. Expression of MUC6 glycoprotein was examined in pancreatic cancer tissues by immunofluorescence and loss of MUC6 was observed. Next, to determine whether MUC6 inhibits tumor growth and metastasis by altering cell adhesion and invasion, recombinant MUC6 cDNA and separate MUC6 N-terminal and C-terminal domains were transfected into pancreatic, colorectal and breast cancer cell lines. The recombinant N- and C-terminal proteins were each seen to oligomerize under non-reducing conditions. Overexpression of both domains of the MUC6 glycoprotein significantly inhibited cell adhesion to matrix proteins (collagen I, collagen IV, fibronectin and laminin) in LS 180 but not in PANC-1 cells. Moreover, the N- and C-terminal domains of MUC6 inhibited invasion of both LS 180 and PANC-1 cells by 40% and 70%, respectively, in comparison with controls. These results suggest that MUC6 may inhibit invasion of tumor cells through the basement membrane of the pancreatic duct and slow the development of infiltrating carcinoma.     

MUC1 enhances tumor progression and contributes toward immunosuppression in a mouse model of spontaneous pancreatic adenocarcinoma

MUC1, a membrane tethered mucin glycoprotein, is overexpressed and aberrantly glycosylated in >80% of human ductal pancreatic adenocarcinoma. However, the role of MUC1 in pancreatic cancer has been elusive, partly due to the lack of an appropriate model. We report the characterization of a novel mouse model that expresses human MUC1 as a self molecule (PDA.MUC1 mice). Pancreatic tumors arise in an appropriate MUC1-tolerant background within an immune-competent host. Significant enhancement in the development of pancreatic intraepithelial preneoplastic lesions and progression to adenocarcinoma is observed in PDA.MUC1 mice, possibly due to increased proliferation. Tumors from PDA.MUC1 mice express higher levels of cyclooxygenase-2 and IDO compared with PDA mice lacking MUC1, especially during early stages of tumor development. The increased proinflammatory milieu correlates with an increased percentage of regulatory T cells and myeloid suppressor cells in the pancreatic tumor and tumor draining lymph nodes. Data shows that during pancreatic cancer progression, MUC1-mediated mechanisms enhance the onset and progression of the disease, which in turn regulate the immune responses. Thus, the mouse model is ideally suited for testing novel chemopreventive and therapeutic strategies against pancreatic cancer.     

MicroRNA-200c Modulates the Expression of MUC4 and MUC16 by Directly Targeting Their Coding Sequences in Human Pancreatic Cancer

Transmembrane mucins, MUC4 and MUC16 are associated with tumor progression and metastatic potential in human pancreatic adenocarcinoma. We discovered that miR-200c interacts with specific sequences within the coding sequence of MUC4 and MUC16 mRNAs, and evaluated the regulatory nature of this association. Pancreatic cancer cell lines S2.028 and T3M-4 transfected with miR-200c showed a 4.18 and 8.50 fold down regulation of MUC4 mRNA, and 4.68 and 4.82 fold down regulation of MUC16 mRNA compared to mock-transfected cells, respectively. A significant reduction of glycoprotein expression was also observed. These results indicate that miR-200c overexpression regulates MUC4 and MUC16 mucins in pancreatic cancer cells by directly targeting the mRNA coding sequence of each, resulting in reduced levels of MUC4 and MUC16 mRNA and protein. These data suggest that, in addition to regulating proteins that modulate EMT, miR-200c influences expression of cell surface mucins in pancreatic cancer.     

胃癌组织中的MUC1和VEGF表达及其意义

目的:检测胃癌组织中VEGF和MUC1的表达情况,研究二者与胃癌生物学行为之间的关系。方法:应用免疫组织化学SP法检测VEGF和MUC1在胃癌组织和癌旁组织中的表达情况。结果:胃癌组织中VEGF的阳性表达明显高于癌旁组织,两者之间差异存在统计学意义(P0.05),VEGF在胃癌组织中的表达与胃癌浸润深度、有无远处转移、有无淋巴结转移、TNM分期有关,之间差异存在统计学意义(P0.05);胃癌组织中MUC1的阳性表达明显高于癌旁组织,两者之间差异存在统计学意义(P0.05),MUC1在胃癌组织中的表达与分化程度、TNM分期、淋巴结转移、远处转移有关,差异有统计学意义(P0.05);胃癌患者组织VEGF与MUC1的表达水平呈正相关(r=0.210,P0.05)。结论:VEGF和MUC1在胃癌发生、发展和转移过程中起重要作用,可能成为检测胃癌的重要肿瘤标志物。     

New insights into pancreatic cancer stem cells

Pancreatic cancer(PC) has been one of the deadliest of all cancers, with almost uniform lethality despite aggressive treatment. Recently, there have been important advances in the molecular, pathological and biological understandingof pancreatic cancer. Even after the emergence of recent new targeted agents and the use of multiple therapeutic combinations, no treatment option is viable in patients with advanced cancer. Developing novel strategies to target progression of PC is of intense interest. A small population of pancreatic cancer stem cells(CSCs) has been found to be resistant to chemotherapy and radiation therapy. CSCs are believed to be responsible for tumor initiation, progression and metastasis. The CSC research has recently achieved much progress in a variety of solid tumors, including pancreatic cancer to some extent. This leads to focus on understanding the role of pancreatic CSCs. The focus on CSCs may offer new targets for prevention and treatment of this deadly cancer. We review the most salient developments in important areas of pancreatic CSCs. Here, we provide a review of current updates and new insights on the role of CSCs in pancreatic tumor progression with special emphasis on Dcl K1 and Lgr5, signaling pathways altered by CSCs, and the role of CSCs in prevention and treatment of PC.     

Expression of MUC17 Is Regulated by HIF1α-Mediated Hypoxic Responses and Requires a Methylation-Free Hypoxia Responsible Element in Pancreatic Cancer

MUC17 is a type 1 membrane-bound glycoprotein that is mainly expressed in the digestive tract. Recent studies have demonstrated that the aberrant overexpression of MUC17 is correlated with the malignant potential of pancreatic ductal adenocarcinomas (PDACs); however, the exact regulatory mechanism of MUC17 expression has yet to be identified. Here, we provide the first report of the MUC17 regulatory mechanism under hypoxia, an essential feature of the tumor microenvironment and a driving force of cancer progression. Our data revealed that MUC17 was significantly induced by hypoxic stimulation through a hypoxia-inducible factor 1α (HIF1α)-dependent pathway in some pancreatic cancer cells (e.g., AsPC1), whereas other pancreatic cancer cells (e.g., BxPC3) exhibited little response to hypoxia. Interestingly, these low-responsive cells have highly methylated CpG motifs within the hypoxia responsive element (HRE, 5'-RCGTG-3'), a binding site for HIF1α. Thus, we investigated the demethylation effects of CpG at HRE on the hypoxic induction of MUC17. Treatment of low-responsive cells with 5-aza-2'-deoxycytidine followed by additional hypoxic incubation resulted in the restoration of hypoxic MUC17 induction. Furthermore, DNA methylation of HRE in pancreatic tissues from patients with PDACs showed higher hypomethylation status as compared to those from non-cancerous tissues, and hypomethylation was also correlated with MUC17 mRNA expression. Taken together, these findings suggested that the HIF1α-mediated hypoxic signal pathway contributes to MUC17 expression, and DNA methylation of HRE could be a determinant of the hypoxic inducibility of MUC17 in pancreatic cancer cells.     

Analysis of T-cell receptor repertoire in peripheral blood of patients with pancreatic cancer and other pancreatic diseases

Pancreatic cancer (PC) has been the fourth cancer-related death worldwide, diagnosed at an unresectable stage due to its rapid progression and few symptoms of this disease at early stages. The aim of this study was to determine the association between the diversity of T-cell receptor (TCR) repertoire and clinicopathological characteristics of patients with PC and other benign pancreatic diseases. In order to make a comprehensive analysis the TCR repertoire, high-throughput sequencing was used to differentiate complementarity determining region 3 (CDR3) of the TCR β chain in peripheral blood samples from 3 PC, 3 chronic pancreatitis, 3 pancreatic cystic lesions and 3 pancreatic neuroendocrine tumour patients. We found that there were significant differences related to TCR repertoire between PC and other pancreatic diseases, and PC is a relatively immunosuppressive tumour. Changes of peripheral TCR repertoire may be used to predict the progression of PC and the response to immunotherapy. And there may exist novel-specific antigens in PC patients which could be used to design targeting immunotherapy in the nearly future.     

Isolation and characterization of the major form of human MUC18 cDNA gene and correlation of MUC18 over-expression in prostate cancer cell lines and tissues with malignant progression.

Ectopical expression of huMUC18, a cell adhesion molecule in the immunoglobulin gene superfamily, causes a non-metastatic human melanoma cell line to become metastatic in a nude mouse system. To determine if MUC18 expression correlates with the development and malignant progression of prostate cancer, we investigated differential expression of human MUC18 (huMUC18) in normal prostate epithelial cells, prostate cancer cell lines, and prostatic normal and cancer tissues. We cloned and characterized the human MUC18 (huMUC18) cDNA gene from three human prostate cancer cell lines and three human melanoma cell lines. The cDNA sequences from the six human cancer cell lines were identical except differences in one to five nucleotides. The deduced amino acid sequences of the longest ORF were 646 amino acids that were identical in these cDNAs except for one to three amino acid residues. The amino acid sequences of all our huMUC18 cDNA genes are similar to that cloned by other group (GenBank access #M28882) except differences in the same seven amino acids. We conclude that huMUC18 cDNA gene reported here represents the gene product from a major allele. The MUC18 mRNA and protein was expressed in three metastatic prostate cancer cell lines (TSU-PR1, DU145, and PC-3), but not in one non-metastatic prostate cancer cell line (LNCaP.FGC). The expression of huMUC18 in these four cell lines is positively related to their extent of in vitro motility and invasiveness and in vivo metastasis in nude mice. HuMUC18 protein was also expressed at high levels in extracts prepared from tissue sample sections containing high grade prostatic intraepithelial neoplasia (PIN), but weakly expressed in extracts prepared from cultured primary normal prostatic epithelial cells and the normal prostate gland. Immunohistochemical analysis showed that huMUC18 was expressed at higher levels in the epithelial cells of high-grade PIN and prostatic carcinomas, and in cells of a perineural invasion, a lymph node, and a lung metastases compared to that in normal or benign hyperplastic epithelium (BPH). We therefore conclude that MUC18 expression is increased during prostate cancer initiation (high grade PIN) and progression to carcinoma, and in metastatic cell lines and metastatic carcinoma. Increased expression of MUC18 is implicated to play an important role in developing and malignant progression of human prostate cancer. Furthermore, the lacking of predominant cytoplasmic membrane expression of MUC18 appeared to correlate with malignant progression of prostate cancer.     

Anti-MUC1 antibody inhibits EGF receptor signaling in cancer cells

MUC1 is a type I transmembrane glycoprotein aberrantly overexpressed in various cancer cells. High expression of MUC1 is closely associated with cancer progression and metastasis, leading to poor prognosis. We previously reported that MUC1 is internalized by the binding of the anti-MUC1 antibody, from the cell surface to the intracellular region via the macropinocytotic pathway. Since MUC1 is closely associated with ErbBs, such as EGF receptor (EGFR) in cancer cells, we examined the effect of the anti-MUC1 antibody on EGFR trafficking. Our results show that: (1) anti-MUC1 antibody GP1.4, but not another anti-MUC1 antibody C595, triggered the internalization of EGFR in pancreatic cancer cells; (2) internalization of EGFR by GP1.4 resulted in the inhibition of ERK phosphorylation by EGF stimulation, in a MUC1 dependent manner; (3) inhibition of ERK phosphorylation by GP1.4 resulted in the suppression of proliferation and migration of pancreatic cancer cells. We conclude that the internalization of EGFR by anti-MUC1 antibody GP1.4 inhibits the progression of cancer cells via the inhibition of EGFR signaling.     

RNF13: a novel RING-type ubiquitin ligase over-expressed in pancreatic cancer

Protein ubiquitination by E3 ubiquitin ligases plays an important role in cancer development. In this study, we provide experimental evidence that a RING-finger-containing protein RNF13 is an ER/Golgi membrane-associated E3 ubiquitin ligase and its RING finger domain is required for the ubiquitin ligase activity. Immunohistochemical analysis of pancreatic ductal adenocarcinoma (PDAC) and paracancerous normal tissues from 72 patients documented RNF13 over-expression in 30 tumor samples (41.7%, 30/72), and its expression was significantly associated with histological grading (P = 0.024). In addition, RNF13 was detected in precancerous lesions: tubular complexes in chronic pancreatitis (CP) and pancreatic intraepithelial neoplasia (PanIN) (79.3%, 23/29 and 62.8%, 22/35, respectively). Moreover, RNF13 staining was significantly correlated with Tenascin-C expression (P = 0.004) in PDAC samples, further supporting the role of RNF13 in cancer progression. Over-expression of wild type but not RING domain-mutant RNF13 in pancreatic MiaPaca-2 cancer cells increased invasive potential and gelatinolytic activity by matrix metalloproteinase-9. Taken together, these findings reveal that RNF13 is a novel E3 ubiquitin ligase involved in pancreatic carcinogenesis; ubiquitin-mediated modification of proteins by RNF13 may participate in pancreatic cancer development.     

The value of immunohistochemical research on PCNA, p53 and heat shock proteins in prostate cancer management: a review

This review addresses the significance of the expression of proliferating cell nuclear antigen (PCNA), p53 and some heat shock proteins (Hsps) in prostate carcinoma (PC). In fact, PCNA and p53 are two widely discussed tools in PC diagnosis, mainly because of the controversy regarding the significance of their expression during prostate cancer development and progression. At the same time, only few studies have shown the potential role of Hsps in carcinogenesis and their overexpression in pre-neoplastic and neoplastic lesions of the prostate. We briefly describe the physiological roles of Hsps in normal cells, and the significance of their immunohistochemical detection in PC as well as in pre-cancerous lesions of the prostate. We will also discuss the possible functional interactions of these molecules in both dysplastic and neoplastic cells.     

Monoclonal antibodies recognizing the non-tandem repeat regions of the human mucin MUC4 in pancreatic cancer

The MUC4 mucin is a high molecular weight, membrane-bound, and highly glycosylated protein. It is a multi-domain protein that is putatively cleaved into a large mucin-like subunit (MUC4α) and a C-terminal growth-factor like subunit (MUC4β). MUC4 plays critical roles in physiological and pathological conditions and is aberrantly overexpressed in several cancers, including those of the pancreas, cervix, breast and lung. It is also a potential biomarker for the diagnosis, prognosis and progression of several malignancies. Further, MUC4 plays diverse functional roles in cancer initiation and progression as evident from its involvement in oncogenic transformation, proliferation, inhibition of apoptosis, motility and invasion, and resistance to chemotherapy in human cancer cells. We have previously generated a monoclonal antibody 8G7, which is directed against the TR region of MUC4, and has been extensively used to study the expression of MUC4 in several malignancies. Here, we describe the generation of anti-MUC4 antibodies directed against the non-TR regions of MUC4. Recombinant glutathione-S-transferase (GST)-fused MUC4α fragments, both upstream (MUC4α-N-Ter) and downstream (MUC4α-C-Ter) of the TR domain, were used as immunogens to immunize BALB/c mice. Following cell fusion, hybridomas were screened using the aforementioned recombinant proteins ad lysates from human pancreatic cell lines. Three anti MUC4α-N-Ter and one anti-MUC4α-C-Ter antibodies were characterized by several inmmunoassays including enzyme-linked immunosorbent assay (ELISA), immunoblotting, immunofluorescene, flow cytometry and immunoprecipitation using MUC4 expressing human pancreatic cancer cell lines. The antibodies also reacted with the MUC4 in human pancreatic tumor sections in immunohistochemical analysis. The new domain-specific anti-MUC4 antibodies will serve as important reagents to study the structure-function relationship of MUC4 domains and for the development of MUC4-based diagnostics and therapeutics.