Limits...
Role of MUC4-NIDO domain in the MUC4-mediated metastasis of pancreatic cancer cells.

Senapati S, Gnanapragassam VS, Moniaux N, Momi N, Batra SK - Oncogene (2011)

Bottom Line: The in vitro studies demonstrated an enhanced invasiveness of MiaPaCa cells expressing MUC4 (MiaPaCa-MUC4) compared with vector-transfected cells (MiaPaCa-Vec; P=0.003) or cells expressing MUC4 without the NIDO domain (MiaPaCa-MUC4-NIDO(Δ); P=0.03).However, the absence of NIDO-domain has no significant role on cell growth and motility (P=0.93).Additionally, a reduced binding (P=0.0004) of MiaPaCa-MUC4-NIDO(Δ) cells to the fibulin-2 coated plates compared with MiaPaCa-MUC4 cells indicated a possible interaction between the MUC4-NIDO domain and fibulin-2, a nidogen-interacting protein.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA.

ABSTRACT
MUC4 is a large transmembrane type I glycoprotein that is overexpressed in pancreatic cancer (PC) and has been shown to be associated with its progression and metastasis. However, the exact cellular and molecular mechanism(s) through which MUC4 promotes metastasis of PC cells has been sparsely studied. Here we showed that the nidogen-like (NIDO) domain of MUC4, which is similar to the G1-domain present in the nidogen or entactin (an extracellular matrix protein), contributes to the protein-protein interaction property of MUC4. By this interaction, MUC4 promotes breaching of basement membrane (BM) integrity, and spreading of cancer cells. These observations are corroborated with the data from our study using an engineered MUC4 protein without the NIDO domain, which was ectopically expressed in the MiaPaCa PC cells, lacking endogenous MUC4 and nidogen protein. The in vitro studies demonstrated an enhanced invasiveness of MiaPaCa cells expressing MUC4 (MiaPaCa-MUC4) compared with vector-transfected cells (MiaPaCa-Vec; P=0.003) or cells expressing MUC4 without the NIDO domain (MiaPaCa-MUC4-NIDO(Δ); P=0.03). However, the absence of NIDO-domain has no significant role on cell growth and motility (P=0.93). In the in vivo studies, all the mice orthotopically implanted with MiPaCa-MUC4 cells developed metastasis to the liver as compared with MiaPaCa-Vec or the MiaPaCa-MUC4-NIDO(Δ) group, hence, supporting our in vitro observations. Additionally, a reduced binding (P=0.0004) of MiaPaCa-MUC4-NIDO(Δ) cells to the fibulin-2 coated plates compared with MiaPaCa-MUC4 cells indicated a possible interaction between the MUC4-NIDO domain and fibulin-2, a nidogen-interacting protein. Furthermore, in PC tissue samples, MUC4 colocalized with the fibulin-2 present in the BM. Altogether, our findings demonstrate that the MUC4-NIDO domain significantly contributes to the MUC4-mediated metastasis of PC cells. This may be partly due to the interaction between the MUC4-NIDO domain and fibulin-2.

Show MeSH

Related in: MedlinePlus

Schematic representation for the proposed action of MUC4-NIDO domain in disrupting the basement membrane integrityNormal pancreatic epithelial cells do not express MUC4; however, in pancreatic cancer, MUC4 is expressed all over the epithelial cells' surface. Through the NIDO domain, the pancreatic cancer-associated MUC4 present in close proximity to the basement membrane, interacts with fibulin-2, and possibly hinders the normal interaction between fibulin-2 and nidogen. Through this interaction MUC4 potentially disrupts the basement membrane integrity by yet undefined non-proteolytic process, as a result of which invasion and metastasis of PC cells is thus mediated by MUC4-NIDO and Fibulin 2 interaction.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3298579&req=5

Figure 6: Schematic representation for the proposed action of MUC4-NIDO domain in disrupting the basement membrane integrityNormal pancreatic epithelial cells do not express MUC4; however, in pancreatic cancer, MUC4 is expressed all over the epithelial cells' surface. Through the NIDO domain, the pancreatic cancer-associated MUC4 present in close proximity to the basement membrane, interacts with fibulin-2, and possibly hinders the normal interaction between fibulin-2 and nidogen. Through this interaction MUC4 potentially disrupts the basement membrane integrity by yet undefined non-proteolytic process, as a result of which invasion and metastasis of PC cells is thus mediated by MUC4-NIDO and Fibulin 2 interaction.

Mentions: In the current study, we postulated that under cancer conditions, through the NIDO-domain, MUC4 present at the basal surface of the epithelial cells may competitively inhibit the normal interaction between fibulin-2 and nidogen protein of the basement membrane (BM) (Ries et al. 2001). During this interaction MUC4 may breach the basement membrane integrity, thus promoting the metastasis of PC cells (Figure 6). Indeed, the effect of MUC4-NIDO domain in enhancing the invasiveness of PC cells, while not affecting the motility of cancer cells in vitro, indicates that the function of MUC4-NIDO domain is associated with the presence of extracellular matrix proteins (Figure 2 A and B). Therefore, during cancer cells metastasis, the MUC4-NIDO domain might have a role in rupturing the basement membrane integrity. However, no overall effect of MUC4 or MUC4-NIDO domain deleted proteins on the incidence of metastasis to sites like spleen, mesentery, peritoneum and diaphragm (Figure 3B, Table-1) might be due to the fact that unlike cancer cells that grow in situ and break the basement membrane for distant organ metastasis, the cancer cells in the orthotopic model don't face the epithelial basement membrane barrier at the primary tumor site. As a result of which, metastasis of the cancer cells to organs like, mesentery, peritoneum and diaphragm, which can mostly occur by peritoneal dissemination from the primary tumor site, might not get influenced due to absence of MUC4-NIDO domain and epithelial-basement membrane proteins interaction. Simultaneously, in the same experimental model, metastasis of MiaPaCa-MUC4 cells to the liver compared to none in MiaPaCa-MUC4-NIDOΔ group strongly supports our hypothesis, and this might be due to the fact that liver metastasis mostly occurs through hematogenous metastasis process, and even though the cancer cells may not face the epithelial basement membrane barrier in the orthotopic model of cancer metastasis, they will have to face the basement membrane of endothelial cells to complete a successful hematogenous metastasis. On the other way, MUC4 presence, aids the PC cells to easily intravasate and/or extravasate from the blood vessels, which is essential for distant organ metastasis (Figure 3B). This argument is further supported by the fact that, MUC4/MUC4-NIDO domain promotes extravasation of cancer cells in vitro (Figure 2C and D). Furthermore, several recent reports have demonstrated extravasation as a key step of cancer metastasis that is regulated by a variety of secreted or cell surface proteins (Ma et al. 2008; Karnoub et al. 2007).


Role of MUC4-NIDO domain in the MUC4-mediated metastasis of pancreatic cancer cells.

Senapati S, Gnanapragassam VS, Moniaux N, Momi N, Batra SK - Oncogene (2011)

Schematic representation for the proposed action of MUC4-NIDO domain in disrupting the basement membrane integrityNormal pancreatic epithelial cells do not express MUC4; however, in pancreatic cancer, MUC4 is expressed all over the epithelial cells' surface. Through the NIDO domain, the pancreatic cancer-associated MUC4 present in close proximity to the basement membrane, interacts with fibulin-2, and possibly hinders the normal interaction between fibulin-2 and nidogen. Through this interaction MUC4 potentially disrupts the basement membrane integrity by yet undefined non-proteolytic process, as a result of which invasion and metastasis of PC cells is thus mediated by MUC4-NIDO and Fibulin 2 interaction.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3298579&req=5

Figure 6: Schematic representation for the proposed action of MUC4-NIDO domain in disrupting the basement membrane integrityNormal pancreatic epithelial cells do not express MUC4; however, in pancreatic cancer, MUC4 is expressed all over the epithelial cells' surface. Through the NIDO domain, the pancreatic cancer-associated MUC4 present in close proximity to the basement membrane, interacts with fibulin-2, and possibly hinders the normal interaction between fibulin-2 and nidogen. Through this interaction MUC4 potentially disrupts the basement membrane integrity by yet undefined non-proteolytic process, as a result of which invasion and metastasis of PC cells is thus mediated by MUC4-NIDO and Fibulin 2 interaction.
Mentions: In the current study, we postulated that under cancer conditions, through the NIDO-domain, MUC4 present at the basal surface of the epithelial cells may competitively inhibit the normal interaction between fibulin-2 and nidogen protein of the basement membrane (BM) (Ries et al. 2001). During this interaction MUC4 may breach the basement membrane integrity, thus promoting the metastasis of PC cells (Figure 6). Indeed, the effect of MUC4-NIDO domain in enhancing the invasiveness of PC cells, while not affecting the motility of cancer cells in vitro, indicates that the function of MUC4-NIDO domain is associated with the presence of extracellular matrix proteins (Figure 2 A and B). Therefore, during cancer cells metastasis, the MUC4-NIDO domain might have a role in rupturing the basement membrane integrity. However, no overall effect of MUC4 or MUC4-NIDO domain deleted proteins on the incidence of metastasis to sites like spleen, mesentery, peritoneum and diaphragm (Figure 3B, Table-1) might be due to the fact that unlike cancer cells that grow in situ and break the basement membrane for distant organ metastasis, the cancer cells in the orthotopic model don't face the epithelial basement membrane barrier at the primary tumor site. As a result of which, metastasis of the cancer cells to organs like, mesentery, peritoneum and diaphragm, which can mostly occur by peritoneal dissemination from the primary tumor site, might not get influenced due to absence of MUC4-NIDO domain and epithelial-basement membrane proteins interaction. Simultaneously, in the same experimental model, metastasis of MiaPaCa-MUC4 cells to the liver compared to none in MiaPaCa-MUC4-NIDOΔ group strongly supports our hypothesis, and this might be due to the fact that liver metastasis mostly occurs through hematogenous metastasis process, and even though the cancer cells may not face the epithelial basement membrane barrier in the orthotopic model of cancer metastasis, they will have to face the basement membrane of endothelial cells to complete a successful hematogenous metastasis. On the other way, MUC4 presence, aids the PC cells to easily intravasate and/or extravasate from the blood vessels, which is essential for distant organ metastasis (Figure 3B). This argument is further supported by the fact that, MUC4/MUC4-NIDO domain promotes extravasation of cancer cells in vitro (Figure 2C and D). Furthermore, several recent reports have demonstrated extravasation as a key step of cancer metastasis that is regulated by a variety of secreted or cell surface proteins (Ma et al. 2008; Karnoub et al. 2007).

Bottom Line: The in vitro studies demonstrated an enhanced invasiveness of MiaPaCa cells expressing MUC4 (MiaPaCa-MUC4) compared with vector-transfected cells (MiaPaCa-Vec; P=0.003) or cells expressing MUC4 without the NIDO domain (MiaPaCa-MUC4-NIDO(Δ); P=0.03).However, the absence of NIDO-domain has no significant role on cell growth and motility (P=0.93).Additionally, a reduced binding (P=0.0004) of MiaPaCa-MUC4-NIDO(Δ) cells to the fibulin-2 coated plates compared with MiaPaCa-MUC4 cells indicated a possible interaction between the MUC4-NIDO domain and fibulin-2, a nidogen-interacting protein.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA.

ABSTRACT
MUC4 is a large transmembrane type I glycoprotein that is overexpressed in pancreatic cancer (PC) and has been shown to be associated with its progression and metastasis. However, the exact cellular and molecular mechanism(s) through which MUC4 promotes metastasis of PC cells has been sparsely studied. Here we showed that the nidogen-like (NIDO) domain of MUC4, which is similar to the G1-domain present in the nidogen or entactin (an extracellular matrix protein), contributes to the protein-protein interaction property of MUC4. By this interaction, MUC4 promotes breaching of basement membrane (BM) integrity, and spreading of cancer cells. These observations are corroborated with the data from our study using an engineered MUC4 protein without the NIDO domain, which was ectopically expressed in the MiaPaCa PC cells, lacking endogenous MUC4 and nidogen protein. The in vitro studies demonstrated an enhanced invasiveness of MiaPaCa cells expressing MUC4 (MiaPaCa-MUC4) compared with vector-transfected cells (MiaPaCa-Vec; P=0.003) or cells expressing MUC4 without the NIDO domain (MiaPaCa-MUC4-NIDO(Δ); P=0.03). However, the absence of NIDO-domain has no significant role on cell growth and motility (P=0.93). In the in vivo studies, all the mice orthotopically implanted with MiPaCa-MUC4 cells developed metastasis to the liver as compared with MiaPaCa-Vec or the MiaPaCa-MUC4-NIDO(Δ) group, hence, supporting our in vitro observations. Additionally, a reduced binding (P=0.0004) of MiaPaCa-MUC4-NIDO(Δ) cells to the fibulin-2 coated plates compared with MiaPaCa-MUC4 cells indicated a possible interaction between the MUC4-NIDO domain and fibulin-2, a nidogen-interacting protein. Furthermore, in PC tissue samples, MUC4 colocalized with the fibulin-2 present in the BM. Altogether, our findings demonstrate that the MUC4-NIDO domain significantly contributes to the MUC4-mediated metastasis of PC cells. This may be partly due to the interaction between the MUC4-NIDO domain and fibulin-2.

Show MeSH
Related in: MedlinePlus