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MMP-2 and TIMP-1 are derived from, not in response to, pancreatic cancer
Mark Bloomston1, Alexis Shafii, Emmanuel E Zervos
1Department of Surgery, University of South Florida, Tampa, Florida 33601, USA.
Introduction:
Genetic therapy aimed at disturbing the balance between matrix metalloproteinases (MMP) and their natural tissue inhibitors (TIMP) in treatment of pancreatic cancer requires an understanding of whether MMP and TIMP are tumor- or host-derived. This study was undertaken to determine whether production of MMP-2 and TIMP-1 is by, or in response to, pancreatic cancer.
Methods:
PANC-1 (poorly differentiated human pancreatic cancer) or CD-1 (PANC cells transfected to overproduce TIMP-1) cells were implanted into the pancreata of 20 nude mice. After sacrifice, tumors and peritumoral stroma underwent immunohistochemical staining for human and murine MMP-2 and TIMP-1. Normal murine pancreas served as control. All stains were reviewed in a "blinded" manner by a pathologist and graded relative to normal control pancreata.
Results:
Control pancreata displayed faint murine MMP-2 and TIMP-1 staining and no human MMP-2 or TIMP-1. MMP-2 was most prominent in peritumoral stroma, while TIMP-1 was most prominent in tumors. CD-1 tumors contained very high levels of TIMP-1 compared to PANC-1 tumors and control pancreata. Tumoral and peritumoral MMP-2 were overwhelmingly human. As well, tumoral TIMP-1 was predominantly human.
Conclusions:
In a murine model for human pancreatic cancer, nearly all TIMP-1 and MMP-2 expression is tumor-derived (i.e., human). Pharmacologic and gene therapy aimed at disturbing the MMP/TIMP balance in pancreatic cancer should be targeted toward tumor-specific mechanisms and warrants continued investigation.
Insights
In pancreatic cancer models, both matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of metalloproteinase-1 (TIMP-1) are primarily produced by the tumor, not the host. This suggests targeting tumor-specific mechanisms for effective gene therapy.
Area of Science:
- Oncology
- Molecular Biology
- Cancer Genetics
Background:
- Pancreatic cancer treatment strategies, including genetic therapy, hinge on understanding the origin of matrix metalloproteinases (MMP) and tissue inhibitors of metalloproteinases (TIMP).
- Distinguishing between tumor-derived and host-derived MMP and TIMP is crucial for developing targeted therapies that disrupt the MMP/TIMP balance.
- This study investigates the cellular source of MMP-2 and TIMP-1 in the context of pancreatic cancer.
Purpose of the Study:
- To determine whether matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of metalloproteinase-1 (TIMP-1) production in pancreatic cancer is by the tumor cells or in response to the host.
- To provide foundational knowledge for the development of targeted genetic and pharmacologic therapies for pancreatic cancer.
Main Methods:
- Human pancreatic cancer cells (PANC-1) and a TIMP-1 overproducing variant (CD-1) were xenografted into nude mice.
- Immunohistochemical staining was performed on tumors, peritumoral stroma, and normal murine pancreas to detect human and murine MMP-2 and TIMP-1.
- Stained samples were evaluated by a pathologist in a blinded manner, comparing expression levels to normal controls.
Main Results:
- Control pancreata showed minimal murine MMP-2 and TIMP-1 staining, with no human protein expression.
- MMP-2 expression was predominantly observed in the peritumoral stroma, while TIMP-1 was concentrated within the tumors.
- Both tumoral and peritumoral MMP-2, as well as tumoral TIMP-1, were overwhelmingly identified as human in origin.
Conclusions:
- In this murine model of human pancreatic cancer, MMP-2 and TIMP-1 are predominantly expressed by the tumor itself.
- These findings support the rationale for targeting tumor-specific MMP/TIMP mechanisms in pancreatic cancer therapy.
- Further investigation into pharmacologic and gene therapy approaches directed at tumor-derived MMP/TIMP is warranted.