Many pancreatic tumors are like fortresses, surrounded by dense collagen and other tissue matrices. These tissues can shield the tumors and help them evade immune therapies, rendering the immune system powerless against the "king of cancers," pancreatic cancer. A research team at the University of Wisconsin-Madison in the United States has pioneered a new approach to pancreatic cancer treatment by using bacteria to penetrate cancerous reinforcements and deliver drugs. The research findings were published in the latest issue of the journal "Cell."
Pancreatic cancer is one of the cancers with the lowest 5-year survival rates among common cancers. Several factors contribute to the difficulty in treating the "king of cancers." The focus of this latest study is on how to break through the "hard barrier" formed by collagen, connective tissue, and other components.
After analyzing a large number of patient tumor samples, the research team discovered that a specific type of carcinogenic collagen was hindering the effectiveness of immune therapy. In light of this, the team chose a bacterium that could penetrate the tough collagen barrier and carry nanomedicine for immune therapy. This bacterium is a strain of E. coli with a proven safety record in humans, and it has an affinity for the hypoxic tumor environment.
The team designed a "protein cage" containing two drugs: one that degrades collagen and another that is an anti-cancer immune checkpoint inhibitor, and then attached these two drugs to the E. coli.
The team tested this delivery system in a mouse model with pancreatic ductal adenocarcinoma. The results showed that mice treated with bacteria exhibited delayed tumor growth and longer survival compared to mice receiving other treatments. Furthermore, among all treatments, using E. coli carrying nanomedicine to treat tumors had the most significant effect on increasing the infiltration of anti-cancer immune cells.
