THBS1/2-integrin β1 axis disruption with THBS1-derived peptides inhibits iCCA tumor growth
Background
Intrahepatic cholangiocarcinoma (iCCA) is an aggressive liver cancer with limited therapeutic options, often characterized by extensive tumor growth and metastatic dissemination. Thrombospondin-1 (THBS1) and Thrombospondin-2 (THBS2), produced by cancer-associated fibroblasts (CAFs) and iCCA cells, are known to promote tumor progression by enhancing malignant cholangiocyte interaction with the extracellular matrix (ECM). A critical gap exists in identifying specific therapeutic targets that effectively disrupt these pro-tumorigenic interactions, which this study addresses by focusing on the THBS1/2-integrin β1 axis.
Study Design
Researchers investigated the role of THBS1/2 in iCCA by identifying integrin α3β1 and α6β1 as their cognate receptors on iCCA cells. They disrupted the THBS1-integrin β1 axis using several approaches: monoclonal antibodies targeting integrin β1, THBS1-derived peptides designed to interfere with binding, and THBS1 knockout (KO) iCCA cells. The effects were evaluated in both two-dimensional and three-dimensional cell adhesion assays, as well as mouse xenograft models to assess tumor formation and growth in vivo. The primary endpoints included integrin β1 activation, ECM adhesion, cell morphology, intracellular junction integrity, and tumor development.
Results
Disruption of the THBS1-integrin β1 axis consistently reduced autocrine and paracrine integrin β1 activation, leading to significantly decreased ECM adhesion in both 2D and 3D assays. Loss of endogenous THBS1 via KO also profoundly altered iCCA cell morphology, weakening intracellular junctions crucial for cell-cell contact and tissue integrity. The most compelling finding emerged from the in vivo studies: > Loss of endogenous THBS1 completely prevented tumor formation in mouse xenograft models, highlighting its critical role in iCCA malignancy. These results collectively identify integrin α3β1 and α6β1 as key receptors for THBS1 and THBS2, and confirm the THBS1/2-integrin β1 axis as a central driver of iCCA cell adhesion and tumor growth.
Key Findings
- Integrin α3β1 and α6β1 are cognate receptors for THBS1 and THBS2 on iCCA cells.
- Disrupting the THBS1-integrin β1 axis reduces autocrine/paracrine integrin β1 activation.
- THBS1-derived peptides decrease iCCA cell adhesion in 2D and 3D assays.
- Loss of endogenous THBS1 alters cell morphology and weakens intracellular junctions.
- THBS1 knockout prevents tumor formation in mouse xenograft models.
Why It Matters
This research identifies the THBS1/2-integrin β1 axis as a promising novel therapeutic target for intrahepatic cholangiocarcinoma (iCCA), a cancer with high unmet need. The demonstration that THBS1-derived peptides can disrupt this axis and prevent tumor formation in vivo suggests a potential new class of interventions. Targeting this pathway could offer a strategy to inhibit iCCA progression by blocking critical tumor-ECM interactions and cell adhesion, potentially improving outcomes for patients. While still in preclinical stages, these findings lay the groundwork for developing specific peptide-based or antibody-based therapies that interfere with THBS1/2 signaling, moving closer to a usable protocol for iCCA treatment.
intrahepatic-cholangiocarcinoma
icca
thbs1
thbs2
integrin-beta1
tumor-growth