Recent research from the NCI-Designated Cancer Center at Sanford Burnham Prebys has shed light on the role of the tumor microenvironment in pancreatic ductal adenocarcinoma (PDAC), a particularly aggressive form of cancer. Published in Cancer Cell, the study explores how cancer cells interact with the surrounding tissues, immune cells, and extracellular matrix, which collectively influence tumor growth and treatment efficacy.
The researchers focused on a cellular process called macropinocytosis, through which PDAC cells absorb nutrients from the extracellular matrix. This process not only fuels cancer cell proliferation but also alters the surrounding environment, making it more fibrous and less accessible to immune cells. By blocking macropinocytosis, the team observed a significant reshaping of the tumor microenvironment, characterized by reduced fibrosis and increased infiltration of immune cells.
The study highlighted the transformation of fibroblasts into cancer-associated fibroblasts (CAFs), which typically support tumor growth. By inhibiting macropinocytosis, the researchers induced a shift in CAFs toward a subtype that promotes inflammation rather than tumor stiffness, thereby enhancing the potential for immune response and drug delivery.
Combining macropinocytosis inhibitors with immunotherapy and chemotherapy resulted in notable improvements in treatment outcomes, including reduced tumor metastasis and prolonged survival in mouse models. The findings suggest that targeting macropinocytosis could be a promising strategy for developing combination therapies, particularly for pancreatic cancer, which ranks as the third leading cause of cancer-related deaths despite representing only a small percentage of cases.
The ongoing research aims to further understand how manipulating the tumor microenvironment can enhance the effectiveness of cancer treatments, offering potential new avenues for therapy in challenging cancers like PDAC.