TIMP-1-expressing breast tumor spheroids for the evaluation of drug penetration and efficacy.

Abundance of stromal cells and extracellular matrix (ECM) is observed in breast cancer, acting as a barrier for drug penetration and presenting a key issue for developing efficient therapeutics. In this study, we aimed to develop a three-dimensional (3D) multicellular tumor model comprising cancer and stromal cells that could effectively mimic the drug resistance properties of breast cancer. Three different types of spheroid models were designed by co-culturing breast cancer cells (MDA-MB-231) with three different types of stromal cells: human adipose-derived stromal cells (hASCs), human bone marrow stromal cells, or human dermal fibroblasts. Compared with other models, in the hASC co-culture model, tissue inhibitor of metalloproteinases-1 (TIMP-1) was highly expressed and the activity of matrix metalloproteinases was decreased, resulting in a higher ECM deposition on the spheroid surfaces. This spheroid model showed less drug penetration and treatment efficacy than the other models. TIMP-1 silencing in hASCs reduced ECM protein expression and increased drug penetration and vulnerability. A quantitative structure-activity relationship study using multiple linear regression drew linear relationships between the chemical properties of drugs and experimentally determined permeability values. Drugs that did not match the drug-likeness rules exhibited lower permeability in the 3D tumor model. Taken together, our findings indicate that this 3D multicellular tumor model may be used as a reliable platform for efficiently screening therapeutics agents for solid tumors.

Boiling Histotripsy-induced Partial Mechanical Ablation Modulates Tumour Microenvironment by Promoting Immunogenic Cell Death of Cancers.

Boiling histotripsy is a promising non-invasive High-Intensity Focused Ultrasound (HIFU) technique that employs HIFU mechanical effects to fractionate solid tumours without causing any significant thermal damage. It has been suggested that boiling histotripsy may induce a strong immune response due to the absence of denatured antigenic protein at the HIFU focus. The underlying immunological mechanisms of this technique are, however, poorly understood. In this study, we demonstrated the feasibility of using boiling histotripsy to mechanically fractionate human breast adenocarcinoma cells (MDA-MB-231) and the potential immunological effects induced by boiling histotripsy, for the first time. Our results showed that mechanical stresses produced by boiling histotripsy promote immunogenic cell death of cancer cells via TNF-induced necrosis signaling pathway. This immunogenic cell death significantly increases secretions of damage-associated molecular patterns (CRT, HSP70, HMGB-1), pro-inflammatory cytokines (IFN-γ, IL-1α, IL-1ß, IL-18) and chemokines (IL-8) which are related to M1 macrophage activation. Furthermore, the levels of these signaling proteins increase with the degree of mechanical damage induced by boiling histotripsy. Together, the results presented can suggest that boiling histotripsy could be a potential therapeutic approach for not only mechanically destroying solid tumours (e.g., breast cancer) but also promoting immunogenic cell death via TNF-induced necrosis to trigger antitumour immunity.

Cytotoxic and anticancer properties of new ruthenium polypyridyl complexes with different lipophilicities.

Three ruthenium complexes containing a bidentate piq ligand, [(piq)Ru(bpy)2]2+ (1), [(piq)Ru(phen)2]2+ (2), and [(piq)Ru(DIP)2]2+ (3) (piq = phenylisoquinolinate, bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline, DIP = 4,7-diphenyl-1,10-phenanthroline), were prepared. The DNA binding properties of complexes 1-3 to double-stranded DNA were studied. The binding of 1-3 to calf-thymus DNA (ct-DNA) yielded lower emission intensities than those observed with the corresponding Ru complexes alone. To explore potential interactions of complexes 1-3 with lipid-rich organs in live cells, the emission properties of the Ru probes were studied with liposomes. The emission intensities of complexes 1-3 were enhanced to similar extents upon interaction with liposomes. The cytotoxic activities of the complexes against MDA-MB-231 and HUVECs were evaluated in vitro. The effects of complexes 1-3 on the survival of MDA-MB-231 cells were examined and compared with that of cis-platin. Complexes 2 and 3 were more cytotoxic to cancer cells than cis-platin. Complexes 1-3 showed cellular uptakes of 1.1, 10.6, and 76.6%, respectively, indicating that the greatest amount of complex 3 entered the cancer cells. Inhibition of cell migration by complexes 1-3 was also evaluated by the wound healing assay.