Slug enhances invasion ability of pancreatic cancer cells through upregulation of matrix metalloproteinase-9 and actin cytoskeleton remodeling

Our plain-English summary of Slug enhances invasion ability of pancreatic cancer cells through upregulation of matrix metalloproteinase-9 and actin cytoskeleton remodeling, by K. Zhang, D. Chen, X. Jiao, et al (Laboratory Investigation; a Journal of Technical Methods and Pathology, 2011).

The study

• Authors: K. Zhang, D. Chen, X. Jiao, S. Zhang, X. Liu, J. Cao, L. Wu, D. Wang
• Journal: Laboratory Investigation; a Journal of Technical Methods and Pathology
• Published: 2011;91(3):426-38
• Cited by: 61 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Slug, a member of the Snail family of transcription factors, has a crucial role in the regulation of epithelial-mesenchymal transition (EMT) by suppressing several epithelial markers and adhesion molecules, including E-cadherin. A recent study demonstrated that no relationship exists between Slug and E-cadherin in pancreatic cancer. Another study showed that in malignant mesothelioma effusions Slug was associated with matrix metalloproteinase (MMP) expression, but that there was no association with E-cadherin. F-ascin is an actin-bundling protein involved in filopodia assembly and cancer invasion and metastasis of multiple epithelial cancer types. In this study, we investigated Slug, E-cadherin, and MMP-9 expression using immunohistochemistry in 60 patients with pancreatic cancer and their correlation with carcinoma invasion and metastasis. Additionally, we observed the effects of Slug on invasion and metastasis in the pancreatic cancer cell line PANC-1. Alterations in Slug, MMP-9, and E-cadherin were determined by RT-PCR, western blot, and immunohistochemistry. Alterations in MMP-9 and F-actin cytoskeleton were determined by immunofluorescence staining, flow cytometry (FCM), or gelatin zymography. Slug, E-cadherin, and MMP-9 expression in pancreatic cancer was significantly associated with lymph node metastases and we found a significant correlation between Slug and MMP-9 expression; however, no significant correlation was observed between Slug and E-cadherin expression. Slug transfection significantly increased invasion and metastasis in PANC-1 cells and orthotopic tumor of mouse in vivo, and significantly upregulated and activated MMP-9; however, there was no effect on E-cadherin expression. Slug promoted the formation of lamelliopodia or filopodia in PANC-1 cells. The intracellular F-actin and MMP-9 was increased and relocated to the front of the extending pseudopodia from the perinuclear pool in Slug-transfected PANC-1 cells. These results suggest that Slug promotes migration and invasion of PANC-1 cells, which may correlate with the reorganization of MMP-9 and remodeling of the F-actin cytoskeleton, but not with E-cadherin expression.

In plain English

This study of pancreatic cancer, from Qingdao University in China, did not involve asbestos. The authors stained tumor samples from 60 consecutive patients with pancreatic adenocarcinoma, collected between 1999 and 2009, for three proteins: Slug, MMP-9 and E-cadherin. Slug was found in 41 (68.3%) of the 60 tumors, MMP-9 in 25 (41%) and E-cadherin in 24 (40%). Each was significantly associated with spread to lymph nodes. Slug was significantly correlated with MMP-9 but not with E-cadherin. The authors then added extra Slug to a pancreatic cancer cell line, PANC-1. These cells made more MMP-9 and showed no significant change in E-cadherin. They contained 2.1-fold more F-actin and crossed a test membrane more often: 117.16 cells per field, against 68.74 for unaltered cells. Adding an MMP inhibitor, BB94, lowered this to 63.14. Mice were injected with the Slug-altered cells. In this group, 10 of 12 had liver spread and 6 of 12 had lung spread. Among mice given control-vector cells, 3 of 12 had liver spread and none had lung spread. The authors concluded that Slug promotes migration and invasion, which may be linked to MMP-9 but not to E-cadherin.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Laboratory study combining staining of human pancreatic cancer tissue with cell-line experiments (adding the Slug gene to cancer cells) and a mouse experiment
• Who was studied: Tissue from 60 consecutive pancreatic adenocarcinoma (ordinary ductal carcinoma) patients, 1999 to 2009, Affiliated Hospital of Medical College, Qingdao University, China. Also the PANC-1 pancreatic cancer cell line, and mice with 12 per group
• Exposure: No asbestos or fiber exposure was studied. The experimental variable was overexpression of the Slug gene in PANC-1 cells, compared with unaltered cells and cells given an empty (control) vector. Some cells were also treated with the MMP inhibitor BB94
• Main results:
  • In the 60 patient tumors, Slug was positive in 41 (68.3%)
  • In the 60 patient tumors, MMP-9 was expressed in 25 (41%) and E-cadherin in 24 (40%)
  • In the patient tumors, Slug, MMP-9 and E-cadherin expression were each significantly associated with nodal metastases (P less than 0.01)
  • In the patient tumors, Slug expression was significantly correlated with MMP-9 expression (P = 0.0034 in Table 2)
  • In the patient tumors, there was no significant relationship between Slug and E-cadherin expression (P greater than 0.05; 0.057 in Table 2)
  • In PANC-1 cells, Slug overexpression gave higher MMP-9 protein than mock-transfected or untransfected cells (P = 0.039)
  • In PANC-1 cells, Slug overexpression caused no significant change in E-cadherin
  • In PANC-1 cells, the MMP inhibitor BB94 decreased the MMP-9 increase caused by Slug
  • Intracellular F-actin increased 2.1-fold in Slug-transfected cells (P less than 0.01 versus control)
  • In Slug-transfected cells, MMP-9 and F-actin were mainly located at the tips of the filopodia; in untreated cells they were mainly near the nucleus
  • In the invasion assay, the number of invading cells was 68.74 plus or minus 7.34 for untreated PANC-1 cells and 117.16 plus or minus 8.45 for Slug-overexpressing cells
  • In the invasion assay, Slug-overexpressing cells treated with BB94 gave 63.14 plus or minus 6.49 invading cells
  • In mice injected with Slug-transfected cells (12 mice), 10 had liver metastases, 6 lung metastases and 2 skin metastases. Differences in lung and liver metastases versus vector-transfected mice were statistically significant
  • In comparison mice, unaltered PANC-1 cells gave liver metastases in 4 mice and lung metastasis in 1 mouse; vector-transfected cells gave liver metastases in 3 mice (Table 3: 0 of 12 with lung metastasis)
• The authors' conclusion: The authors concluded that Slug promotes migration and invasion of pancreatic cancer cells. They said this may correlate with upregulation of MMP-9 and remodeling of the F-actin cytoskeleton, but not with E-cadherin expression. They said further study is needed to clarify the mechanisms

Topics

Medical terms in this study, explained in our Lexicon: Mesothelioma, Metastasis, Immunohistochemistry, Carcinoma.

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