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Desmoglein 2 is a substrate of kallikrein 7 in pancreatic cancer.

Ramani VC, Hennings L, Haun RS - BMC Cancer (2008)

Bottom Line: BxPC-3 cells stably transfected to overexpress hK7 were used to examine the effect of hK7 on cell-surface resident Dsg2.The levels of immunoreactive Dsg1 and Dsg2 were reduced in pancreatic adenocarcinomas compared with both normal pancreatic and chronic pancreatitis tissues.When hK7 was overexpressed in this cell line, there was a significant increase in the amount of soluble Dsg2 released into the culture medium compared with vector-transfected control cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Pathology, Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA. vpramani@uab.edu

ABSTRACT

Background: In a previous report we have demonstrated that the chymotryptic-like serine protease kallikrein 7 (KLK7/hK7) is overexpressed in pancreatic cancer. In normal skin, hK7 is thought to participate in skin desquamation by contributing in the degradation of desmosomal components, such as desmogleins. Thus, the ability of hK7 to degrade desmogleins was assessed and the effect of hK7 expression on desmoglein 2 was examined in cultured pancreatic cancer cells.

Methods: The expression of Dsg1, Dsg2, and Dsg3 in pancreatic tissues was examined by immunohistochemistry and their expression in two pancreatic cancer cell lines, BxPC-3 and Panc-1, was determined by western blot analysis. The ability of hK7 to degrade Dsg1 and Dsg2 was investigated using in vitro degradation assays. BxPC-3 cells stably transfected to overexpress hK7 were used to examine the effect of hK7 on cell-surface resident Dsg2.

Results: The levels of immunoreactive Dsg1 and Dsg2 were reduced in pancreatic adenocarcinomas compared with both normal pancreatic and chronic pancreatitis tissues. Among the desmosomal proteins examined, Dsg2 exhibited robust expression on the surface of BxPC-3 cells. When hK7 was overexpressed in this cell line, there was a significant increase in the amount of soluble Dsg2 released into the culture medium compared with vector-transfected control cells.

Conclusion: A reduction in the amount of the cell adhesion components Dsg1 and Dsg2 in pancreatic tumors suggests that loss of these desmosomal proteins may play a role in pancreatic cancer invasion. Using in vitro degradation assays, both Dsg1 and Dsg2 could be readily proteolyzed by hK7, which is overexpressed in pancreatic adenocarcinomas. The enforced expression of hK7 in BxPC-3 cells that express significant amounts of Dsg2 resulted in a marked increase in the shedding of soluble Dsg2, which is consistent with the notion that aberrant expression of hK7 in pancreatic tumors may result in diminished cell-cell adhesion and facilitate tumor cell invasion.

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Desmoglein 2 staining is lower in pancreatic cancer cell membranes compared to normal and chronic pancreatitis tissue. Representative pancreatic tissue sections stained for Dsg2 showed high levels of membrane staining in (A) normal pancreas and (B) chronic pancreatitis (CP) samples. Membrane staining was much weaker in (C) pancreatic adenocarcinoma (PaC) samples. Original magnification x400. (D) Staining intensity of the cell membranes was quantitated (see Methods), categorized into intensity ranges from 0+ to 3+, and the average percentage of cells in each group was determined and represented in a stacked graph for each tissue type (n = 6).
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Figure 2: Desmoglein 2 staining is lower in pancreatic cancer cell membranes compared to normal and chronic pancreatitis tissue. Representative pancreatic tissue sections stained for Dsg2 showed high levels of membrane staining in (A) normal pancreas and (B) chronic pancreatitis (CP) samples. Membrane staining was much weaker in (C) pancreatic adenocarcinoma (PaC) samples. Original magnification x400. (D) Staining intensity of the cell membranes was quantitated (see Methods), categorized into intensity ranges from 0+ to 3+, and the average percentage of cells in each group was determined and represented in a stacked graph for each tissue type (n = 6).

Mentions: Six independent sections of normal human pancreas, chronic pancreatitis, or pancreatic adenocarcinoma tissue were stained for desmogleins 1, 2, and 3. Desmogleins 1 and 2 were clearly present in all of the normal pancreatic tissue samples examined and showed intense staining at the cell-cell borders (Fig. 1A and 2A, respectively). In contrast, Dsg3 was not detected in any of the pancreatic tissues (data not shown). The chronic pancreatitis samples showed staining intensity and distribution similar to the normal pancreatic samples for Dsg1 (Fig. 1B) and Dsg2 (Fig. 2B). All the pancreatic cancer samples displayed an intense desmoplastic response, the synthesis and deposition of collagenous material by stromal myofibroblasts surrounding the adenocarcinoma, and the membrane staining for both Dsg1 (Fig. 1C) and Dsg2 (Fig. 2C) was distinctly weaker in most of the cancer samples analyzed. The correspondence between increased hK7 expression in pancreatic tumors and loss of Dsg2 is highlighted in the immunohistochemistry studies we have performed. For example, the tumor section stained for Dsg2 (Figure 2C, this study), showing a loss of Dsg2 immunoreactivity, is from the same tissue used to demonstrate increased hK7 expression in pancreatic tumors (Figure 2A, ref. [13]).


Desmoglein 2 is a substrate of kallikrein 7 in pancreatic cancer.

Ramani VC, Hennings L, Haun RS - BMC Cancer (2008)

Desmoglein 2 staining is lower in pancreatic cancer cell membranes compared to normal and chronic pancreatitis tissue. Representative pancreatic tissue sections stained for Dsg2 showed high levels of membrane staining in (A) normal pancreas and (B) chronic pancreatitis (CP) samples. Membrane staining was much weaker in (C) pancreatic adenocarcinoma (PaC) samples. Original magnification x400. (D) Staining intensity of the cell membranes was quantitated (see Methods), categorized into intensity ranges from 0+ to 3+, and the average percentage of cells in each group was determined and represented in a stacked graph for each tissue type (n = 6).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2628383&req=5

Figure 2: Desmoglein 2 staining is lower in pancreatic cancer cell membranes compared to normal and chronic pancreatitis tissue. Representative pancreatic tissue sections stained for Dsg2 showed high levels of membrane staining in (A) normal pancreas and (B) chronic pancreatitis (CP) samples. Membrane staining was much weaker in (C) pancreatic adenocarcinoma (PaC) samples. Original magnification x400. (D) Staining intensity of the cell membranes was quantitated (see Methods), categorized into intensity ranges from 0+ to 3+, and the average percentage of cells in each group was determined and represented in a stacked graph for each tissue type (n = 6).
Mentions: Six independent sections of normal human pancreas, chronic pancreatitis, or pancreatic adenocarcinoma tissue were stained for desmogleins 1, 2, and 3. Desmogleins 1 and 2 were clearly present in all of the normal pancreatic tissue samples examined and showed intense staining at the cell-cell borders (Fig. 1A and 2A, respectively). In contrast, Dsg3 was not detected in any of the pancreatic tissues (data not shown). The chronic pancreatitis samples showed staining intensity and distribution similar to the normal pancreatic samples for Dsg1 (Fig. 1B) and Dsg2 (Fig. 2B). All the pancreatic cancer samples displayed an intense desmoplastic response, the synthesis and deposition of collagenous material by stromal myofibroblasts surrounding the adenocarcinoma, and the membrane staining for both Dsg1 (Fig. 1C) and Dsg2 (Fig. 2C) was distinctly weaker in most of the cancer samples analyzed. The correspondence between increased hK7 expression in pancreatic tumors and loss of Dsg2 is highlighted in the immunohistochemistry studies we have performed. For example, the tumor section stained for Dsg2 (Figure 2C, this study), showing a loss of Dsg2 immunoreactivity, is from the same tissue used to demonstrate increased hK7 expression in pancreatic tumors (Figure 2A, ref. [13]).

Bottom Line: BxPC-3 cells stably transfected to overexpress hK7 were used to examine the effect of hK7 on cell-surface resident Dsg2.The levels of immunoreactive Dsg1 and Dsg2 were reduced in pancreatic adenocarcinomas compared with both normal pancreatic and chronic pancreatitis tissues.When hK7 was overexpressed in this cell line, there was a significant increase in the amount of soluble Dsg2 released into the culture medium compared with vector-transfected control cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Pathology, Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA. vpramani@uab.edu

ABSTRACT

Background: In a previous report we have demonstrated that the chymotryptic-like serine protease kallikrein 7 (KLK7/hK7) is overexpressed in pancreatic cancer. In normal skin, hK7 is thought to participate in skin desquamation by contributing in the degradation of desmosomal components, such as desmogleins. Thus, the ability of hK7 to degrade desmogleins was assessed and the effect of hK7 expression on desmoglein 2 was examined in cultured pancreatic cancer cells.

Methods: The expression of Dsg1, Dsg2, and Dsg3 in pancreatic tissues was examined by immunohistochemistry and their expression in two pancreatic cancer cell lines, BxPC-3 and Panc-1, was determined by western blot analysis. The ability of hK7 to degrade Dsg1 and Dsg2 was investigated using in vitro degradation assays. BxPC-3 cells stably transfected to overexpress hK7 were used to examine the effect of hK7 on cell-surface resident Dsg2.

Results: The levels of immunoreactive Dsg1 and Dsg2 were reduced in pancreatic adenocarcinomas compared with both normal pancreatic and chronic pancreatitis tissues. Among the desmosomal proteins examined, Dsg2 exhibited robust expression on the surface of BxPC-3 cells. When hK7 was overexpressed in this cell line, there was a significant increase in the amount of soluble Dsg2 released into the culture medium compared with vector-transfected control cells.

Conclusion: A reduction in the amount of the cell adhesion components Dsg1 and Dsg2 in pancreatic tumors suggests that loss of these desmosomal proteins may play a role in pancreatic cancer invasion. Using in vitro degradation assays, both Dsg1 and Dsg2 could be readily proteolyzed by hK7, which is overexpressed in pancreatic adenocarcinomas. The enforced expression of hK7 in BxPC-3 cells that express significant amounts of Dsg2 resulted in a marked increase in the shedding of soluble Dsg2, which is consistent with the notion that aberrant expression of hK7 in pancreatic tumors may result in diminished cell-cell adhesion and facilitate tumor cell invasion.

Show MeSH
Related in: MedlinePlus