Disease relevance of MUC6

• Aberrant expression of MUC5AC and MUC6 gastric mucins and sialyl Tn antigen in intraepithelial neoplasms of the pancreas [1].
• MUC6 was also expressed in 16 cases of type II intestinal metaplasia and in 11 cases of type III intestinal metaplasia [2].
• PDX1 and MUC6 double positive expression was observed in carcinomas, respectively, including the corpus, and also correlated with histological type and depth of invasion [3].
• CONCLUSIONS: Our results suggest that gel forming mucins (more particularly MUC5AC and MUC6) may have a role in epithelial wound healing after mucosal injury in inflammatory bowel diseases in addition to mucosal protection [4].
• Expression of MUC6 is frequently preserved in pancreatic and bile duct adenocarcinomas, but it is only sparsely expressed in endocervical carcinomas [5].

Psychiatry related information on MUC6

• The expression of mucin genes, MUC 3, 4, 5AC, 5B, 6, 7, and 8 in human fetal tissues was examined to establish the localisation and age of onset of expression of each mucin gene during human development [6].
• The original diagnosis has been revised to that of a unique case of mucin-producing parathyroid cancer with an extraordinarily long latency period before recurrence [7].
• Luminal P2 receptors may play a role in intestinal defense mechanisms with both fluid and mucin secretion aiding in the removal of noxious agents from the mucosal surface [8].
• Expression of the core blood group structures sialosyl Tn (STn) and Tn is regarded as a colorectal cancer-specific change reflecting truncated synthesis of the oligosaccharide component of goblet cell mucin [9].
• Longer reaction times up to 2 h completely removed the O-linked carbohydrate chains from fetuin and ovine submaxillary mucin [10].

High impact information on MUC6

• This rolling phenomenon is mediated by adhesive interactions between lectin containing adhesion molecules, termed selectins, on both the vascular endothelium and leukocytes, and carbohydrate ligands immobilized on mucin-like scaffolds [11].
• In section i, structure, expression, and localization of the 18 human MUC genes and MUC gene products having tandem repeat domains and the specificity and application of MUC-specific antibodies that identify mucin gene products in airway tissues, cells, and secretions are overviewed [12].
• Specific inflammatory/immune response mediators can activate mucin gene regulation and airway remodeling, including goblet cell hyperplasia (GCH) [12].
• These processes sustain airway mucin overproduction and contribute to airway obstruction by mucus and therefore to the high morbidity and mortality associated with these diseases [12].
• Fractalkine, a novel transmembrane molecule with a CX3C-motif chemokine domain atop a mucin stalk, induces both adhesion and migration of leukocytes [13].

Chemical compound and disease context of MUC6

• All invasive carcinomas expressing MUCSAC were positive for MUC1 and four were positive for MUC6 [14].
• A series of experiments were conducted to study synthesis and secretion of mucin in mucus-secreting subpopulations of HT29 human colonic adenocarcinoma cells selected by resistance to methotrexate (MTX) [15].
• The synthesis and secretion of mucin-like high-molecular glycoprotein was studied in 2 human colon cancer cell lines that spontaneously differentiate in culture (Caco-2 and T84) and in 2 cell lines that do not spontaneously differentiate (LS174T and HT29) [16].
• Bile acid-induced alterations of mucin production in differentiated human colon cancer cell lines [17].
• Muc4/sialomucin complex (SMC) is a high molecular mass heterodimeric membrane mucin, encoded by a single gene, and originally discovered in a highly metastatic ascites rat mammary adenocarcinoma [18].

Biological context of MUC6

• Recent information on the order of the mucin genes at chromosome 11p15 suggests that MUCX may be MUC6, one of the already identified mucin genes, or a novel one, yet to be fully characterized [19].
• The carboxyl-terminal sequence of the human secretory mucin, MUC6. Analysis Of the primary amino acid sequence [20].
• MUC6 transcripts were evident in the pancreatic ducts from 13 weeks of gestation and at high levels in the stomach at 23 weeks [6].
• Both cases of MUC6 positivity and 1/5 cases of MUC5AC positivity were confined to the ulcer associated cell lineage [21].
• The MUC6 secretory mucin was originally isolated from a gastric cDNA library [5].

Anatomical context of MUC6

• In contrast, MUC6 peptide expression was limited to mucous neck cells of the fundus, antral-type glands of the antrum and cardia, and Brunner's glands of the duodenum [22].
• MUC3 and MUC6 were constantly and focally expressed, respectively, in the biliary epithelial cells in the intrahepatic large bile ducts in normal livers, extrahepatic biliary obstruction, and, also, hepatolithiasis [23].
• BACKGROUND: In normal gastric epithelium, MUC5AC is detected in superficial epithelium associated with Lewis type 1 antigens and MUC6 is detected in antral glands with Lewis type 2 [24].
• The data obtained show that MUC6 is highly expressed in gastric mucosa, duodenal Brunner's glands, gall bladder, seminal vesicle, pancreatic centroacinar cells and ducts, and periductal glands of the common bile duct; focal expression is seen in basal endometrial and endocervical glands [5].
• CONCLUSIONS: These results suggest that 11p15 mucins MUC2 and MUC6 are related to lymph node metastasis in SACL [25].

Associations of MUC6 with chemical compounds

• The best specificity, negative results on all peripheral blood mononuclear (PBMN) cell samples from healthy donors, were shown for MUC2, MUC5B and MUC6 RT-PCR assays [26].
• MUC6 expression in breast tissues and cultured cells: abnormal expression in tumors and regulation by steroid hormones [27].
• Reactivity with antibodies against the Le(b) structure (where Le represents the Lewis antigen) followed the MUC5AC distribution, whereas antibodies against the Le(y) structure and reactivity with the GlcNAc-selective Solanum tuberosum lectin coincided with MUC6, suggesting that the two mucins are glycosylated differently [28].
• An inhibitor of Sp family binding, mithramycin A, suppressed MUC6 transcripts, and Sp1 and Sp3 overexpression up-regulated them [29].
• METHODS: Formalin fixed, paraffin wax embedded tissue from 69 cases of invasive breast carcinoma and surrounding breast tissue was studied immunohistochemically with monoclonal antibodies against MUC1 (SM3), MUCSAC (CLH2), and MUC6 (CLH6), using the avidin-biotin-peroxidase method [14].

Other interactions of MUC6

• Five of the 6 cases with MUC2 expression and 6 of the 11 cases with MUC6 expression were had lymph node metastasis [25].
• No transcripts for MUC5AC, MUC5B or MUC 6 were detected in any of these specimens [30].
• Endometrial epithelium expresses MUC1 and low amounts of MUC6 [31].
• TFF1, TFF2, and MUC6 were found in 84%, 92%, and 65% of GMD, respectively [32].
• Ulcerating BE was distinguished by very low expression of MUC6 and MUC5B, but very high expression of TFF1 [33].

Analytical, diagnostic and therapeutic context of MUC6

• MUC6, isolated from a stomach cDNA library, is mainly expressed in stomach antral glands, as detected by using in situ hybridization and immunohistochemistry [27].
• We examined MUC6 expression in normal and pathological breast tissues using immunohistochemistry with MUC6-specific antibodies and in cultured breast cancer cells using immunocytochemistry and Northern blotting [27].
• Following ion-exchange HPLC, both MUC5AC and MUC6 appeared as several distinct populations, probably corresponding to 'glycoforms' of the mucins, the most highly charged of which were found in the gland tissue [28].
• The loss of hormone dependence in this prostate cancer xenograft model is therefore marked by irreversible histological alterations, mucinous or neuro-endocrine, associated with an expression of secretory MUC2, MUC5B and MUC6, independent of the histological differentiation subtype [34].
• In conclusion, MUC1 and MUC6 expression in BE is distinct from that of the cardia and antrum with intestinal metaplasia; thus, immunophenotyping for these markers may have some value in a subset of patients in helping to separate BE from patients with intestinal metaplasia of the cardia [35].

References