Carboxyl-terminal polypeptide fragment of MUC16 combing stathmin1 promotes gallbladder cancer cell migration and invasion.

CA-125, coded by MUC16 gene, is responsible to many kinds of tumor metastasis. However, the related mechanism remains unclear. We have established a novel manner to reveal gallbladder cancer metastasis related to serum CA-125 levels through the C-terminal polypeptide of MUC16 gene production. MUC16 C-terminal polypeptide significantly promoted gallbladder cancer cell migration and invasion in vitro. Mass spectrum indicated that interaction of MUC16 C-terminal fragment with the C-terminal domain of stathmin1 inhibited the phosphorylation of stathmin1 to promote the combination with tubulin. Stathmin1 knockdown inhibited the migration and invasion of gallbladder cancer cells in vitro and lung metastasis in vivo induced by MUC16 C-terminal polypeptide. The high expression level of MUC16c consistent with stathmin1 was also confirmed in gallbladder cancer tissues. Our study revealed the underlying mechanism of gallbladder cancer metastasis related to CA-125 levels, which was beneficial for CA-125 in gallbladder cancer diagnose and therapy.

MUC16 facilitates cervical cancer progression via JAK2/STAT3 phosphorylation-mediated cyclooxygenase-2 expression.

OBJECTIVES: MUC16 (mucin 16, also known as CA-125, cancer antigen 125, carcinoma antigen 125, or carbohydrate antigen 125) has been predicted as tumor biomarker for therapy. We determined to investigate effects and regulatory mechanism of MUC16 on cervical tumorigenesis. METHODS: Expression levels of MUC16 in cervical cancer cell lines was analyzed via qRT-PCR (quantitative real-time polymerase chain reaction). Knockdown of MUC16 was conducted via shRNA (Short hairpin RNA) transfection. MTT and colony formation assays were used to investigate effect of MUC16 on cell proliferation. Wound healing assay was utilized to detect migration and transwell assay to detect invasion. The underlying mechanism was demonstrated via western blot analysis. RESULTS: MUC16 was elevated in cervical cancer cell lines. MUC16 knockdown inhibited cell proliferation, invasion and migration. Gain- and loss-of functional assays revealed that over-expression of MUC16 activated Janus Kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) via phosphorylation, thus facilitating cyclooxygenase-2 (COX-2) expression, while knockdown of MUC16 demonstrated the reverse effect on JAK2/STAT3 activation and COX-2 expression. Moreover, inhibition of JAK2/STAT3 attenuated the regulation of MUC16 on COX-2. CONCLUSIONS: MUC16 enhanced proliferation and invasion of cervical cancer cells via JAK2/STAT3 phosphorylation-mediated cyclooxygenase-2 expression, suggesting the potential therapeutic target ability of MUC16 to treat cervical cancer.

The Ocular Surface Glycocalyx and its Alteration in Dry Eye Disease: A Review.

Many studies have revealed that transmembrane mucins, large glycoproteins with heavily glycosylated glycans, are essential for maintaining ocular surface epithelium lubrication and wettability. Recent reports indicate that transmembrane mucins and galectin-3, a chimera type of galectin that binds ß-galactoside in the glycan, play a crucial role in maintaining the epithelial glycocalyx barrier. This review summarizes current evidence regarding the role of galectin-3, the role of the three major transmembrane mucins (i.e., MUC1, MUC4, and MUC16), in the maintenance of ocular surface wettability and transcellular barrier. Pathological mechanisms of glycocalyx barrier disruption and epithelial surface wettability decreases in dry eye disease are also summarized. Lastly, new ophthalmic drugs that target transmembrane mucin are described.

Downregulation of cell surface CA125/MUC16 induces epithelial-to-mesenchymal transition and restores EGFR signalling in NIH:OVCAR3 ovarian carcinoma cells.

BACKGROUND: Epithelial ovarian cancer (EOC) cells are prone to metastasise throughout the peritoneal cavity. The epithelial-to-mesenchymal transition (EMT) is a necessary step towards metastatic tumour progression. CA125/MUC16 mucin is a high-molecular-weight glycoprotein overexpressed in the majority of serous carcinomas, suggesting a possible role in the pathogenesis of these cancers. METHODS: The role of CA125/MUC16 in EMT was investigated using single-chain antibody-mediated knockdown of cell surface CA125/MUC16 in overexpressing EOC NIH:OVCAR3 cells. RESULTS: CA125/MUC16 knockdown was associated with morphological alterations along with decreased surface expression of epithelial markers (E-cadherin, cytokeratin-18) and increased expression of mesenchymal markers (N-cadherin, vimentin). Co-immunoprecipitation experiments revealed that CA125/MUC16 binds to E-cadherin and ß-catenin complexes. The in vitro studies showed disruption of cell-cell junctions, enhanced motility, migration and invasiveness in CA125/MUC16 knockdown cells. Enhanced epidermal growth factor receptor (EGFR) activation was observed in CA125/MUC16 knockdown cells along with increased Akt and ERK1/2 phosphorylation, which are downstream effectors of EGFR, and increased MMP-2 and MMP-9 expression and activities. Epidermal growth factor receptor inhibition strongly inhibited the motility of CA125/MUC16 knockdown cells. CONCLUSIONS: Our findings suggest that CA125/MUC16 plays a role in EMT, presumably through its interaction with E-cadherin and ß-catenin complexes and by modulating EGFR and its downstream signalling pathway in NIH:OVCAR3 cells.

Membrane-tethered mucins have multiple functions on the ocular surface.

Membrane-tethered mucins are large glycoproteins present in the glycocalyx along the apical surface of all wet-surfaced epithelia of the body, including that of the ocular surface. Originally thought to function only in epithelial surface lubrication and hydration, data now indicate that the mucins are multifunctional molecules, each having unique as well as common functions. This review summarizes current knowledge regarding the three major membrane mucins of the ocular surface, MUC1, MUC4, and MUC16. The mucins vary in their ocular surface distribution, size, structural motifs, and functions. The ectodomains of each are released into the tear film and are, thus, a component of the soluble mucins of the tear film. Both animal and in vitro models for their study are herein described, as are alterations of the mucins in ocular surface disease.

Serum CA 125 expression as a tumor marker for diagnosis and monitoring the clinical course of epithelioid sarcoma.

PURPOSE: We report here, our experience of seven patients with epithelioid sarcomas and their serum CA 125 levels, as well as the results of an in vitro and in vivo study of CA 125 expression in epithelioid sarcoma cells and xenografts using three epithelioid sarcoma cell lines. METHODS: In the clinical study, the serum CA 125 levels of seven epithelioid sarcoma patients were examined at multiple time points. Expression of the MUC16 gene that encodes the CA 125 sequence was examined using RT-PCR methods in three epithelioid sarcoma cell lines, FU-EPS-1, SFT-8606 and NEPS, and the CA 125 protein in each cell lysate was examined by Western blot using anti-CA 125 clone OC125 antibody. The concentration of CA 125 in the conditioned medium of each cell line was also measured. RESULTS: In five of the seven epithelioid sarcoma patients, CA 125 levels reflected regression and progression of their disease. The CA 125 concentrations in the conditioned medium of FU-EPS-1, SFT-8606 and NEPS cells were 259, 252, and 6 U/ml, respectively. Strong expression of MUC16 mRNA was shown in FU-EPS-1 and SFT-8606 cells: correspondingly, a thick band was observed by Western blot analysis in only FU-EPS-1 and SFT-8606 cells. CONCLUSION: We concluded that epithelioid sarcoma cells produce and secrete CA 125 into the blood serum and that the elevation of serum CA 125 correlates with disease progression. Therefore, measuring the serum CA 125 level should provide an useful index for diagnosing and monitoring the course of epithelioid sarcoma.

[Tumor Marker CA125: biochemical and molecular properties]. / L'antigène carbohydrate CA125: propriétés biochimiques et moléculaires.

Antigen carbohydrate CA125 is a tumor marker used in the monitoring of epithelial ovarian cancers. It is a transmembranaire glycoprotein with a high molecular weight. It is a mucin with a carbohydrate content estimated to be 24-28%. CA125 is encoded by the gene MUC16 which is rich of tandem repeats. Different hypothesis were suggested concerning the mechanism of secretion of CA125 that could be soluble or attached to the cellular surface. This last form of CA125 has many molecular interactions such as with mesothelin and galectin. These interactions play a key role in the stimulation and the dissemination of ovarian cancer via the tumor marker CA125.

CA125/MUC16 is dispensable for mouse development and reproduction.

Cancer antigen 125 (CA125) is a blood biomarker that is routinely used to monitor the progression of human epithelial ovarian cancer (EOC) and is encoded by MUC16, a member of the mucin gene family. The biological function of CA125/MUC16 and its potential role in EOC are poorly understood. Here we report the targeted disruption of the of the Muc16 gene in the mouse. To generate Muc16 knockout mice, 6.0 kb was deleted that included the majority of exon 3 and a portion of intron 3 and replaced with a lacZ reporter cassette. Loss of Muc16 protein expression suggests that Muc16 homozygous mutant mice are null mutants. Muc16 homozygous mutant mice are viable, fertile, and develop normally. Histological analysis shows that Muc16 homozygous mutant tissues are normal. By the age of 1 year, Muc16 homozygous mutant mice appear normal. Downregulation of transcripts from another mucin gene (Muc1) was detected in the Muc16 homozygous mutant uterus. Lack of any prominent abnormal phenotype in these Muc16 knockout mice suggests that CA125/MUC16 is not required for normal development or reproduction. These knockout mice provide a unique platform for future studies to identify the role of CA125/MUC16 in organ homeostasis and ovarian cancer.

siRNA-mediated Erc gene silencing suppresses tumor growth in Tsc2 mutant renal carcinoma model.

Silencing of gene expression by small interfering RNAs (siRNAs) is rapidly becoming a powerful tool for genetic analysis and represents a potential strategy for therapeutic product development. However, there are no reports of systemic delivery of siRNAs for stable treatment except short hairpin RNAs (shRNAs). On the other hand, there are many reports of systemic delivery of siRNAs for transient treatment using liposome carriers and others. With regard to shRNAs, a report showed fatality in mice due to oversaturation of cellular microRNA/short hairpin RNA pathways. Therefore, we decided to use original siRNA microspheres instead of shRNA for stable treatment of disease. In this study, we designed rat-specific siRNA sequences for Erc/mesothelin, which is a tumor-specific gene expressed in the Eker (Tsc2 mutant) rat model of hereditary renal cancer and confirmed the efficacy of gene silencing in vitro. Then, by using siRNA microspheres, we found that the suppression of Erc/mesothelin caused growth inhibition of Tsc2 mutant renal carcinoma cells in tumor implantation experiments in mice.

Rules of tumor cell development and their application to biomarkers for ovarian cancer.

PURPOSE/OBJECTIVES: To apply the Hanahan and Weinberg conceptual framework for tumor development to the specific biomarkers observed or expressed in ovarian cancer. DATA SOURCES: Data-based publications, topical reviews, and book chapters. DATA SYNTHESIS: Articles specific to ovarian cancer were reviewed to examine whether the six rules from the Hanahan and Weinberg conceptual framework were applicable to biomarkers of ovarian cancer. This approach allows for the application of a general framework for the development of solid tumors to the development of ovarian cancer. CONCLUSIONS: The six rules for tumor cell development outlined in the Hanahan and Weinberg conceptual framework are applicable to biomarkers expressed or observed in patients with ovarian cancer. IMPLICATIONS FOR NURSING: Oncology nurses can enhance their clinical teaching by integrating this information into their practice. Nurses who conduct research on ovarian cancer can use this framework to guide the selection of biomarker(s) for these studies. Finally, nurse educators can use this framework when teaching students key concepts in the care of patients with cancer.

Functions of MUC16 in corneal epithelial cells.

PURPOSE: The membrane-associated mucin MUC16, a heavily O-glycosylated transmembrane protein, is expressed by the ocular surface epithelia and localized on the tips of the surface microplicae. Although its functions in the ocular surface glycocalyx are unknown, it is thought that MUC16 provides a disadhesive barrier to the epithelial membrane. Two other membrane-associated mucins expressed by ocular surface epithelia, MUC1 and MUC4, are multifunctional and have signaling capabilities through their cytoplasmic tails and EGF-like domains, respectively. The MUC16 cytoplasmic tail has not been characterized, but, because it contains a polybasic amino acid sequence, it potentially interacts with the actin cytoskeleton through ezrin/radixin/moesin (ERM) actin-binding proteins. METHODS: The interaction of MUC16 with the actin cytoskeleton through ERMs was investigated using cytoplasmic tail peptides and ERM pull-down experiments. MUC16 functions were determined using RNA interference in immortalized human corneal-limbal epithelial (HCLE) cells. The effect of MUC16 knockdown on microplicae structure in HCLE cells was determined using scanning and immunoelectron microscopy. HCLE cells were incubated with rose bengal dye to measure the role of MUC16 in ocular surface barrier function. Binding of fluorescently labeled Staphylococcus aureus to HCLE cells was measured to determine the role of MUC16 in the protection of pathogen adherence on the ocular surface epithelium. RESULTS: MUC16 cytoplasmic tail peptides bound the N-terminus of ERMs, with no detectable binding of MUC1 and MUC4 peptides. No effect on surface membrane projections could be detected in HCLE cells after MUC16 suppression; however, HCLE cells incubated with rose bengal showed that exclusion of the dye was significantly reduced in cells with MUC16 suppression. In addition, S. aureus binding to HCLE cells was significantly increased with MUC16 suppression. CONCLUSIONS: These results suggest that MUC16 is a multifunctional molecule linked to the actin cytoskeleton. The expression of MUC16 in the ocular surface glycocalyx helps provide a disadhesive protective barrier for the epithelial surface.

Ovarian cancer antigen CA 125 influences adhesion of human and mammalian cell lines in vitro.

Despite the widespread use of CA 125 for diagnostic and therapeutic evaluation of ovarian cancer function, the molecular nature of CA 125 is only poorly understood. It has been shown that CA 125 enhances the invasiveness of a benign endometriotic cell line in vitro. The invasiveness of cells is controlled by proteolytic activity, cell motility and cell adhesion. Therefore, we determined the influence of CA 125 on the cell adhesion of human carcinoma cell lines in vitro. In all tested human and mammalian cell lines (HECIA, AN3-CA, RL95-2, SK-OV-3, OAW-42, PA-1, HeLa, MCF7, T-47D, A-673, RT112, EJ28, EEC 145, CHO, MDBK, MDCK. LLC-PK1) the cell adhesion in vitro was significantly impaired by CA 125 in a time-dependent manner. Treatment of cells with trypsin diminished the effect of CA 125 on cell adhesion for two hours. By inhibition of protein synthesis with cycloheximide (2 microg/ml) the influence of trypsin on the anti-adhesive effect of CA 125 was significantly prolonged. The results suggest that the ovarian cancer antigen CA 125 influences cell adhesion in vitro.

[The role of CA125 in the differential diagnosis of primary ovarian carcinoma and metastatic ovarian carcinoma originated from the gastrointestinal tract].

OBJECTIVE: To assess the role of CA125 monoclonal antibody in the differential diagnosis of primary ovarian carcinoma and metastatic ovarian carcinoma originated from the gastrointestinal tract. METHODS: Immunohistochemical study using CA125 monoclonal antibody was performed on 33 primary ovarian cancer and 50 metastatic ovarian cancer of gastrointestinal origin. RESULTS: The positivity of CA125 was 84.5% in 33 cases of primary ovarian carcinoma, while in 50 metastatic ovarian carcinoma cases, only 4.0% was CA125 positive. The positivity of CA125 was significantly higher in primary ovarian carcinoma than metastatic ovarian carcinoma (P < 0.001). CONCLUSION: CA125 monoclonal antibody is useful in the differential diagnosis of ovarian carcinoma.

Epidermal growth factor enhances secretion of the ovarian tumor-associated cancer antigen CA125 from the human amnion WISH cell line.

OBJECTIVE: We studied the relation between epidermal growth factor (EGF)/epidermal growth factor receptor (EGFR) and CA125 production in WISH cells. METHODS: We investigated quantitatively and immunohistochemically EGF-stimulated CA125 release from WISH cells and the effect of EGF on CA125 phosphorylation. RESULTS: Immunohistochemical staining demonstrated that CA125 and EGFR expression on the plasma membrane of the WISH cells was closely correlated with cell density. The WISH cell monolayers (day 4) stained for CA125 in both the cytoplasm and plasma membrane. By day 8, cells began to form clumps in the surrounding monolayer that were positive for membrane-associated CA125 and EGFR, while the monolayer was almost negative for both molecules. Four-day and 8-day cells exposed to EGF demonstrated a loss of both CA125 and EGFR staining. Epidermal growth factor increased the secreted CA125 levels by 50% in day-4 cells but had no effect on day-8 cells. CA125 from WISH cells was phosphorylated, and EGF further enhanced this phosphorylation.