Institute of Fundamental Technological Research

The HIFU ablation technique is limited by the long duration of the procedure, which results from the large difference between the size of the HIFU beam’s focus and the tumor size. Ablation of large tumors requires treating them with a sequence of single HIFU beams, with a specific time interval in-between. The aim of this study was to evaluate the biological effects induced in a malignant solid tumor of the rat mammary gland, implanted in adult Wistar rats, during HIFU treatment according to a new ablation plan which allowed researchers to significantly shorten the duration of the procedure. We used a custom, automated, ultrasound imaging-guided HIFU ablation device. Tumors with a 1 mm thickness margin of healthy tissue were subjected to HIFU. Three days later, the animals were sacrificed, and the HIFU-treated tissues were harvested. The biological effects were studied, employing morphological, histological, immunohistochemical, and ultrastructural techniques. Massive cell death, hemorrhages, tissue loss, influx of immune cells, and induction of pro-inflammatory cytokines were observed in the HIFU-treated tumors. No damage to healthy tissues was observed in the area surrounding the safety margin. These results confirmed the efficacy of the proposed shortened duration of the HIFU ablation procedure and its potential for the treatment of solid tumors.

HIFU thermal ablation, breast cancer model, treatment plan, morphology, histology, ultrastructure, immune response, cell death, apoptosis, necrosis

Hemoglobin (Hb) performs its physiological function within the erythrocyte. Extracellular Hb has prooxidative and proinflammatory properties and is therefore sequestered by haptoglobin and bound by the CD163 receptor on macrophages. In the present study, we demonstrate a novel process of Hb uptake by macrophages independent of haptoglobin and CD163. Unexpectedly, macrophages do not degrade the entire Hb, but instead transfer it to neighboring cells. We have shown that the phenomenon of Hb transfer from macrophages to other cells is mainly mediated by extracellular vesicles. In contrast to the canonical Hb degradation pathway by macrophages, Hb transfer has not been reported before. In addition, we have used the process of Hb transfer in anticancer therapy, where macrophages are loaded with a Hb-anticancer drug conjugate and act as cellular drug carriers. Both mouse and human macrophages loaded with Hb-monomethyl auristatin E (MMAE) effectively killed cancer cells when co-cultured in vitro.

Hemoglobin,Macrophages,CD163,Extracellular vesicles,Monomethyl auristatin E