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

Abstract

MUC5AC is a secretory mucin aberrantly expressed in various cancers. In lung cancer, MUC5AC is overexpressed in both primary and metastatic lesions; however, its functional role is not well understood. The present study was aimed at evaluating mechanistic role of MUC5AC on metastasis of lung cancer cells. Clinically, the overexpression of MUC5AC was observed in lung cancer patient tissues and was associated with poor survival. In addition, the overexpression of Muc5ac was also observed in genetically engineered mouse lung adenocarcinoma tissues (KrasG12D; Trp53R172H/+; AdCre) in comparison with normal lung tissues. Our functional studies showed that MUC5AC knockdown resulted in significantly decreased migration in two lung cancer cell lines (A549 and H1437) as compared with scramble cells. Expression of integrins (α5, β1, β3, β4 and β5) was decreased in MUC5AC knockdown cells. As both integrins and MUC5AC have a von Willebrand factor domain, we assessed for possible interaction of MUC5AC and integrins in lung cancer cells. MUC5AC strongly interacted only with integrin β4. The co-localization of MUC5AC and integrin β4 was observed both in A549 lung cancer cells as well as genetically engineered mouse adenocarcinoma tissues. Activated integrins recruit focal adhesion kinase (FAK) that mediates metastatic downstream signaling pathways. Phosphorylation of FAK (Y397) was decreased in MUC5AC knockdown cells. MUC5AC/integrin β4/FAK-mediated lung cancer cell migration was confirmed through experiments utilizing a phosphorylation (Y397)-specific FAK inhibitor. In conclusion, overexpression of MUC5AC is a poor prognostic marker in lung cancer. MUC5AC interacts with integrin β4 that mediates phosphorylation of FAK at Y397 leading to lung cancer cell migration.

Abrogation of MUC5AC Expression Contributes to the Apoptosis and Cell Cycle Arrest of Colon Cancer Cells

“…24 Besides, silencing of MUC5AC participated in decreased proliferation and metastatic properties of lung cancer cells through the regulation of FAK signaling. 16 Our results indicated that, in colon cancer, the inhibition of MUC5AC could significantly induce the apoptosis and cell cycle arrest and also repress the metastatic properties of the colon cancer cell line SW620.…”

“…15 MUC5AC knockdown resulted in significantly decreased expression of integrins (a5, b1, b3-b5) and the phosphorylation of FAK, leading to the impaired ability of migration in the lung cancer cell line. 16 Of note, the mechanisms of oncoprotein MUC5AC in colon cancer need to be further identified.…”

MUC16 Regulates TSPYL5 for Lung Cancer Cell Growth and Chemoresistance by Suppressing p53

“…The cells were incubated in a humidified atmosphere at 37°C with 5% CO 2 . Human specific MUC16-shRNA (pSUPER-Retro-shMUC16 seq1 and pSUPER-Retro-shMUC16 seq2) and mouse specific pSUPER-Retro-shmuc16 constructs were used for stable transfection of MUC16 in H292, H1975 and K1418 with respective control shRNA (4,22). …”

“…Animals that were positive for Kras G12D were infected with AdCre-Luciferase retroviral vector intra-nasally (University of Iowa, Gene and vector core, Iowa, USA). Eight weeks post-infection, the animals were injected with luciferin intra-peritoneally to monitor the tumor growth (22). Mice were fed with food and water ad libitum and subjected to 12 hrs light/dark cycle.…”

“…The blots were incubated with following primary antibodies with respective dilutions: MUC16 (mouse, 1:1000), MUC16 (mouse, 1:1000), pJAK2 #8082, JAK2 #3230, pSTAT3 #9145, STAT3 #12640, GR #12041, pSrc #2101 (Rabbit, 1:2000, Cell signaling technology), E-cadherin (mouse, 1:1500) and N-cadherin (mouse, 1:1500) antibodies were a kind gift from Dr Keith R Johnson, UNMC, Omaha, NE, USA, CK-18 (mouse, 1:1500, Abcam #668), TSPYL5 (rabbit 1:500, Santa Cruz Technology, #sc-98185), p53 (mouse 1:500, Santa Cruz Technology, #sc-126) and anti-β-actin (mouse 1:5000, Sigma #A1978)) (diluted in 2% BSA in PBS). Similarly, immunoprecipitation assay was performed as described previously (22). The signals were detected with the ECL chemiluminescence kit (Amersham Bioscience, UK).…”