Proof of Concept of the Radiosensitizing Effect of Gadolinium Oxide Nanoparticles in Cell Spheroids and a Tumor-Implanted Murine Model of Chondrosarcoma

Gadolinium Oxide Nanoparticles Reinforce the Fractionated Radiotherapy-Induced Immune Response in Tri-Negative Breast Cancer via cGAS-STING Pathway

Introduction

Radiotherapy is a widely recognized first-line clinical treatment for cancer, but its efficacy may be impeded by the radioresistance of advanced tumors. It is urgent to improve the sensitivity of radioresistant tumors to radiotherapy. In this work, gadolinium oxide nanocrystals (GONs) were utilized as radiosensitizers to enhance the killing effect and reinforce the immune activation of X-ray irradiation on 4T1 breast cancer cells in vitro and in vivo.

Methods

1.0 T small animal MR imaging (MRI) system was employed to trace GONs in vivo, while 225 kVp X-ray irradiation equipment was utilized for investigating the radiosensitization of GONs in 4T1 breast cancer cells in vitro and in vivo. Western blot, quantitative real-time PCR (RT-qPCR), immunohistochemistry, immunofluorescence, clonal survival assay, flow cytometry and reactive oxygen species assay were used to explore the biological mechanism of GON sensitization.

Results

GONs exhibited exceptional utility as contrast agents for both in vivo and in vitro MRI imaging. Interestingly, a single dose of 8.0 Gy X-rays together with GONs failed to confer superior therapeutic effects in tumor-bearing mice, while only 3.0 Gy × 3 fractions X-rays combined with GONs exhibited effective tumor growth inhibition. Moreover, fractionated X-ray irradiation with GONs demonstrated a superior capacity to activate the cGAS-STING pathway.

Discussion

Fractionated X-ray irradiation in the presence of GONs has demonstrated the most significant activation of the anti-tumor immune response by boosting the cGAS-STING pathway.

In vitro hyperspectral biomarkers of human chondrosarcoma cells in nanoparticle-mediated radiosensitization using carbon ions

New therapeutic approaches are needed for the management of the highly chemo- and radioresistant chondrosarcoma (CHS). In this work, we used polyethylene glycol-encapsulated iron oxide nanoparticles for the intracellular delivery of the chemotherapeutic doxorubicin (IONPDOX) to augment the cytotoxic effects of carbon ions in comparison to photon radiation therapy. The in vitro biological effects were investigated in SW1353 chondrosarcoma cells focusing on the following parameters: cell survival using clonogenic test, detection of micronuclei (MN) by cytokinesis blocked micronucleus assay and morphology together with spectral fingerprints of nuclei using enhanced dark-field microscopy (EDFM) assembled with a hyperspectral imaging (HI) module. The combination of IONPDOX with ion carbon or photon irradiation increased the lethal effects of irradiation alone in correlation with the induction of MN. Alterations in the hyperspectral images and spectral profiles of nuclei reflected the CHS cell biological modifications following the treatments, highlighting possible new spectroscopic markers of cancer therapy effects. These outcomes showed that the proposed combined treatment is promising in improving CHS radiotherapy.

Combination of Genomic Landsscape and 3D Culture Functional Assays Bridges Sarcoma Phenotype to Target and Immunotherapy

Genomic-based precision medicine has not only improved tumour therapy but has also shown its weaknesses. Genomic profiling and mutation analysis have identified alterations that play a major role in sarcoma pathogenesis and evolution. However, they have not been sufficient in predicting tumour vulnerability and advancing treatment. The relative rarity of sarcomas and the genetic heterogeneity between subtypes also stand in the way of gaining statistically significant results from clinical trials. Personalized three-dimensional tumour models that reflect the specific histologic subtype are emerging as functional assays to test anticancer drugs, complementing genomic screening. Here, we provide an overview of current target therapy for sarcomas and discuss functional assays based on 3D models that, by recapitulating the molecular pathways and tumour microenvironment, may predict patient response to treatments. This approach opens new avenues to improve precision medicine when genomic and pathway alterations are not sufficient to guide the choice of the most promising treatment. Furthermore, we discuss the aspects of the 3D culture assays that need to be improved, such as the standardisation of growth conditions and the definition of in vitro responses that can be used as a cut-off for clinical implementation.