Search

Pancreatic cancer is characterized by a densely fibrotic stroma. The fibrotic stroma hinders the intratumoral penetration of nanomedicine and diminishes therapeutic efficacy. Fibrosis is characterized by an abnormal organization of extracellular matrix (ECM) components, namely the abnormal deposition and/or orientation of collagen and fibronectin. Abnormal ECM organization is chiefly driven by pathological signaling in pancreatic stellate cells (PSCs), the main cell type involved in fibrogenesis. However, whether targeting signaling pathways involved in abnormal ECM organization improves the intratumoral penetration of nanomedicines is unknown. Here, we show that targeting transforming growth factor-β (TGFβ)/Rho-associated kinase (ROCK) 1/2 signaling in PSCs normalizes ECM organization and concomitantly improves macromolecular permeability of the fibrotic stroma. Using a 3-dimensional cell culture model of the fibrotic pancreatic cancer microenvironment, we found that pharmacological inhibition of TGFβ or ROCK1/2 improves the permeation of various macromolecules. By using an isoform-specific pharmacological inhibitor and siRNAs, we show that targeting ROCK2, but not ROCK1, alone is sufficient to normalize ECM organization and improve macromolecular permeability. Moreover, we found that ROCK2 inhibition/knockdown attenuates Yes-associated protein (YAP) nuclear localization in fibroblasts co-cultured with pancreatic cancer cells in 3D. Finally, pharmacological inhibition or siRNA-mediated knockdown of YAP normalized ECM organization and improved macromolecular permeability. Our results together suggest that the TGFβ/ROCK2/YAP signaling axis may be therapeutically targeted to normalize ECM organization and improve macromolecular permeability to augment therapeutic efficacy of nanomedicines in pancreatic cancer., Competing Interests: Declaration of competing interest Takuya Miyazaki is the CEO and Horacio Cabral is the co-founder and the head of drug discovery of Red Arrow Therapeutics, Inc. All other authors declare no conflict of interests., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Pancreatic cancer is notorious for its poor prognosis. The histopathologic characteristic of pancreatic ductal adenocarcinoma (PDAC), which is the most common type of pancreatic cancer, is fibrosis within tumor tissue. Although fibrosis within tumor tissue is thought to impede drug therapy by interfering with the intratumoral accumulation of anti-tumor drugs, this hypothesis has yet to be proven directly in preclinical models. Here, we evaluated the effect of enhanced fibrosis on intratumoral accumulation of macromolecular drugs by increasing fibrosis in a murine tumor model of subcutaneously xenografted BxPC-3, a human PDAC cell line. When fibroblast growth factor-2 (FGF-2) was co-administered upon BxPC-3 inoculation, stromal fibrotic area was increased and was characterized by augmented murine collagen accumulation compared to inoculation of BxPC-3 alone, which correlated with increased monocyte/macrophage contents in the tumor tissues. We further discovered that the intratumoral accumulation of intravenously administrated fluorescein isothiocyanate-dextran of 2,000,000Da (2MDa) was significantly reduced in the FGF-2 co-administered tumors despite unaltered hyaluronan accumulation and pericyte coverage of the tumor neovasculature and increased lymphangiogenesis. Finally, we found that FGF-2 co-administered tumors are more refractory to macromolecular drug therapy using nab-paclitaxel (Abraxane). The model established and analyzed in this study, characterized by increased fibrotic component, provides a preclinical animal model suited to predict the intratumoral accumulation of macromolecular drugs and to evaluate the efficacy of drugs targeting the tumor stroma., (Copyright © 2016 Elsevier B.V. All rights reserved.)