Overexpression of beta3/gamma2 chains of laminin-5 and MMP7 in biliary cancer

Abstract

Aim: To clarify the clinicopathological significance of laminin-5 gamma2 (LNgamma2) and beta3 (LNbeta3) chains and MMP7 expression in biliary tract cancer.

Methods: We analyzed the association between immunohistochemically detected LNgamma2, LNbeta3, and MMP7 expression in biliary tract cancer and clinicopathological characteristics. Activity of MMP7 was analyzed by casein zymography. An in vitro invasion assay after treatment with MMP7-specific siRNA was performed.

Results: LNgamma2 expression was predominantly observed in carcinoma cells at the invasive front. LNgamma2 expression was seen in 57% of patients with biliary tract cancer, and was associated with depth of invasion, histologic type, and advanced stage. The expression pattern of LNbeta3 was classified into two types: invasive front dominant type (38%) and diffuse type (28%). The invasive front dominant type was associated with histologic type and advanced stage. MMP7 positivity was correlated with LNgamma2 or LNbeta3 expression but not with clinicopathological characteristics. Active MMP7 detected by casein zymography was correlated with depth of invasion and advanced stage. Downregulation of MMP7 expression by siRNA resulted in a significant decrease in biliary tract cancer cell invasion in vitro.

Conclusion: Our results suggest that LNgamma2 and LNbeta3, in conjunction with MMP7, play a key role in the progression of biliary tract cancer.

Figure 1

RT-PCR analysis of the LNα3, LNβ3, LNγ2 genes in biliary tract cancer cell lines. 1: MEC; 2: TFK-1; 3: HuH28; 4: TGBC1TKB; 5: TGBC2TKB; 6: TGBC14TKB; 7: TKKK.

Figure 2

LNγ2 expression in biliary tract cancer tissues. A, B: Extrahepatic bile duct cancer tissues; A: Moderately differentiated tubular adenocarcinoma positive for staining. Note that LNγ2 is strongly positive in tumor cells at the invasive front; B: Papillary adenocarcinoma negative for staining; C, D: Gallbladder cancer tissues; C: Moderately differentiated tubular adenocarcinoma positive for staining; D: Well differentiated tubular adenocarcinoma negative for staining; E, F: Carcinoma tissues of the ampulla of Vater; E: Moderately differentiated tubular adenocarcinoma positive for staining. Note that LNγ2 is strongly positive in tumor cells at the invasive front; F: Well differentiated tubular adenocarcinoma negative for staining.

Figure 3

LNβ3 expression in biliary tract cancer tissues. A-C: Extrahepatic bile duct cancer tissues; A: Well differentiated tubular adenocarcinoma positive for invasive front dominant staining; B: Papillary adenocarcinoma positive for diffuse staining; C: Moderately differentiated tubular adenocarcinoma negative for staining; D-F: Gallbladder cancer tissues; A-C: Extrahepatic bile duct cancer tissues; D: Moderately differentiated tubular adenocarcinoma positive for invasive front dominant staining; E: Papillary adenocarcinoma positive for diffuse staining; G-I: Carcinoma tissues of the ampulla of Vater; G: Well differentiated tubular adenocarcinoma positive for invasive front dominant staining; H: Well differentiated tubular adenocarcinoma positive for diffuse staining; I: Well differentiated tubular adenocarcinoma negative for staining.

Figure 4

MMP7 expression in biliary tract cancer tissues. A, B: Extrahepatic bile duct cancer tissues; A: Moderately differentiated tubular adenocarcinoma positive for staining. Note that MMP7 is strongly positive in tumor cells at the invasive front; B: Papillary adenocarcinoma negative for staining; C, D: Gallbladder cancer tissues; C: Moderately differentiated tubular adenocarcinoma positive for staining; D: Well differentiated tubular adenocarcinoma negative for staining; E, F: Carcinoma tissues of the ampulla of Vater; E: Moderately differentiated tubular adenocarcinoma positive for staining. Note that MMP7 is strongly positive in tumor cells at the invasive front; F: Well differentiated tubular adenocarcinoma negative for staining.

Figure 5

Casein zymography of surgical specimen pairs of biliary tract carcinoma and adjacent nontumor tissue. N and T: Matched samples from nontumor and tumor tissue, respectively.

Figure 6

In vitro invasion assay with or without TIMP1 (250 ng/mL) in TFK-1 and siRNA transfectants. Each column indicates the means of three experiments; ^bP < 0.01.