Previous indirect 2D co-culture studies have demonstrated that mesenchymal stem cells (MSCs) promote breast cancer (BC) progression through secretion of paracrine factors including growth factors, cytokines and chemokines. In order to investigate this aspect of the tumour microenvironment in a more relevant 3D co-culture model, spheroids incorporating breast cancer cells (BCCs), both cell lines and primary BCCs expanded as patient-derived xenografts, and MSCs were established. MSCs in co-cultures were shown to enhance proliferation of estrogen receptor (ER)/progesterone receptor (PR)-positive BCCs. In addition, co-culture resulted in downregulation of E-cadherin in parallel with upregulation of the epithelial-mesenchymal transition (EMT)-relation transcription factor, SNAIL. Cytoplasmic relocalization of ski-related novel protein N (SnON), a negative regulator of transforming growth factor-beta (TGF-β) signalling, and of β-catenin, involved in a number of pathways including Wnt signalling, was also observed in BCCs in co-cultures in contrast to monocultures. In addition, the β-catenin inhibitor, 3-[[(4-methylphenyl)sulfonyl]amino]-benzoic acid methyl ester (MSAB), mediated reduced growth and invasion in the co-cultures. This study highlights the potential role for SnON as a biomarker for BC invasiveness, and the importance of interactions between TGF-β and Wnt signalling, involving SnON. Such pathways may contribute towards identifying possible targets for therapeutic intervention in BC patients.

Background and aims: Esophageal adenocarcinoma (EAC) is chemoresistant in the majority of cases. The tumor-promoting biology of cancer associated fibroblasts (CAF) make them a target for novel therapies. Phosphodiesterase type 5 inhibitors (PDE5i) have been shown to regulate the activated fibroblast phenotype in benign disease. We investigated the potential for CAF modulation in EAC using PDE5i to enhance the efficacy of chemotherapy. Methods: EAC fibroblasts were treated with PDE5i and phenotypic effects examined using immunoblotting, immunohistochemistry, gel contraction, transwell invasion, organotypics, single cell RNAseq and shotgun proteomics. The combination of PDE5i with standard-of-care chemotherapy (Epirubicin, 5-Fluorouracil and Cisplatin) was tested for safety and efficacy in validated near-patient model systems (3D tumor growth assays (3D-TGAs) and patient derived xenograft (PDX) mouse models). Results: PDE5i treatment reduced α–SMA expression in CAFs by 50% (p<0.05), associated with a significant reduction in the ability of CAFs to contract collagen-1 gels and induce cancer cell invasion, (p<0.05). RNAseq and proteomic analysis of CAF and EAC cell lines revealed PDE5i specific regulation of pathways related to fibroblast activation and tumor promotion. 3D-TGA assays confirmed the importance of stromal cells to chemoresistance in EAC, which could be attenuated by PDE5i. Chemotherapy+PDE5i in PDX-bearing mice was safe and significantly reduced PDX tumor volume (p<0.05). Conclusion: PDE5 is a candidate for clinical trials to alter the fibroblast phenotype in esophageal cancer. We demonstrate the specificity of PDE5i for fibroblasts to prevent transdifferentiation and revert the CAF phenotype. Finally, we confirm the efficacy of PDE5i in combination with chemotherapy in close-to-patient in vitro and in vivo PDX-based model systems.

The spatial resolution and light detected in fluorescence imaging for small animals are limited by light scattering, absorption and autofluorescence. To address this, novel near-infrared fluorescent contrast agents and imaging configurations have been investigated. In this paper, the influence of the light wavelength and imaging configurations (full-field illumination system and scanning system) on fluorescence imaging are compared quantitatively. The surface radiance for both systems is calculated by modifying the simulation tool Near-Infrared Fluorescence and Spectral Tomography. Fluorescent targets are embedded within a scattering medium at different positions. The surface radiance and spatial resolution are obtained for emission wavelengths between 620 nm and 1000 nm. It was found that the spatial resolution of the scanning system is independent of the tissue optical properties, whereas for full-field illumination, the spatial resolution degrades at longer wavelength. The full width at half maximum obtained by the scanning system is 25% lower than that obtained by the full-field illumination system when the targets are located in the middle of the phantom. The results indicate that although imaging at near-infrared wavelength can achieve a higher surface radiance, it may produce worse spatial resolution.

The therapeutic efficacy of anticancer nanocarriers ishighly dependent on their size, shape, targeting ability, andstimuli-responsiveness. Herein, we studied the in vivo therapeutic efficacy ofDoxorubicin (Dox) loaded redox responsive micellar-like nanoparticles (MNPs)based on linear 2-hydroxypropyl methacrylamide (HPMA) via histopathologicalevaluations. The therapeutic efficacy of DOX-loaded micellar-like Nanoparticlessignificantly improved while the side effects reduced as confirmed byhistopathological examinations. H&E and tunnel staining of tumor tissuesindicated the higher population of apoptotic tumor cells in both treatmentgroups containing DOX. These redox responsive crosslinked HPMA-basedmicellar-like nanoparticles with acceptable therapeutic efficacy and apoptosisinduction in cancerous cells proved to be promising nanomedicine for breast cancer chemotherapy.