A synergistic approach for modulating the tumor microenvironment to enhance nano-immunotherapy in sarcomas.

The lack of properly perfused blood vessels within tumors can significantly hinder the distribution of drugs, leading to reduced treatment effectiveness and having a negative impact on the quality of life of patients with cancer. This problem is particularly pronounced in desmoplastic cancers, where interactions between cancer cells, stromal cells, and the fibrotic matrix lead to tumor stiffness and the compression of most blood vessels within the tumor. To address this issue, two mechanotherapy approaches-mechanotherapeutics and ultrasound sonopermeation-have been employed separately to treat vascular abnormalities in tumors and have reached clinical trials. Here, we performed in vivo studies in sarcomas, to explore the conditions under which these two mechanotherapy strategies could be optimally combined to enhance perfusion and the efficacy of nano-immunotherapy. Our findings demonstrate that combination of the anti-histamine drug ketotifen, as a mechanotherapeutic, and sonopermeation effectively alleviates mechanical forces by decreasing 50 % collagen and hyaluronan levels and thus, reshaping the tumor microenvironment. Furthermore, the combined therapy normalizes the tumor vasculature by increasing two-fold the pericytes coverage. This combination not only improves six times tumor perfusion but also enhances drug delivery. As a result, blood vessel functionality is enhanced, leading to increased infiltration by 40 % of immune cells (CD4+ and CD8+ T-cells) and improving the antitumor efficacy of Doxil nanomedicine and anti-PD-1 immunotherapy. In conclusion, our research underscores the unique and synergistic potential of combining mechanotherapeutics and sonopermeation. Both approaches are undergoing clinical trials to enhance cancer therapy and have the potential to significantly improve nano-immunotherapy in sarcomas.

Nanomechanical properties of solid tumors as treatment monitoring biomarkers.

Many tumors, such as types of sarcoma and breast cancer, stiffen as they grow in a host healthy tissue, while individual cancer cells are becoming softer. Tumor stiffening poses major pathophysiological barriers to the effective delivery of drugs and compromises treatment efficacy. It has been established that normalization of the mechanical properties of a tumor by targeting components of the tumor microenvironment (TME) enhances the delivery of anti-cancer agents and consequently the therapeutic outcome. Consequently, there is an urgent need for the development of biomarkers, which characterize the mechanical state of a particular tumor for the development of personalized treatments or for monitoring therapeutic strategies that target the TME. In this work, Atomic Force Microscopy (AFM) was used to assess human and murine nanomechanical properties from tumor biopsies. In the case of murine tumor models, the nanomechanical properties during tumor progression were measured and a TME normalization drug (tranilast) along with chemotherapy doxorubicin were employed in order to investigate whether AFM has the ability to capture changes in the nanomechanical properties of a tumor during treatment. The nanomechanical data were further correlated with ex vivo characterization of structural components of the TME. The results highlighted that nanomechanical properties alter during cancer progression and AFM measurements are sensitive enough to capture even small alterations during different types of treatments, namely normalization and chemotherapy. The identification of unique AFM-based nanomechanical properties can lead to the development of biomarkers for treatment prediction and monitoring. STATEMENT OF SIGNIFICANCE: Cancer progression is associated with vast remodeling of the tumor microenvironment resulting in changes in the mechanical properties of the tissue. Indeed, many tumors stiffen as they grow and this stiffening compromises treatment efficacy. As a result, a number of treatments target tumor microenvironment in order to normalize its mechanical properties. Consequently, there is an urgent need for the development of innovative tools that can assess the mechanical properties of a particular tumor and monitor tumor progression and treatment outcomes. This work highlights the use of atomic force microscopy (AFM) for assessing the elasticity spectrum of solid tumors at different stages and during treatment. This knowledge is essential for the development of AFM-based nanomechanical biomarkers for treatment prediction and monitoring.