Search Results (6)

Background/Objectives: Sarcomas exhibit marked intratumoural heterogeneity at the molecular, cellular and tissue levels, thereby limiting drug delivery and treatment response. Herein, we evaluated the effects of free doxorubicin (FDOX) and liposomal doxorubicin (LDOX) combined with inductive moderate hyperthermia (IMH) on intratumoural heterogeneity in an experimental sarcoma model using magnetic resonance imaging (MRI), histology and immunohistochemistry image analysis. Methods: Female non-inbred rats bearing sarcoma-45 were divided into six groups: control (no treatment), IMH, FDOX, LDOX, FDOX + IMH and LDOX + IMH. FDOX or LDOX was administered every other day for a total of five times, beginning from day 2 after inoculation. IMH was applied locally following drug administration using a 42 MHz radiofrequency electromagnetic field. Treatment-induced changes were assessed by T₁- and T₂-weighted MRI, haematoxylin–eosin–orange (H&E) staining, and Ki-67 and p53 immunohistochemistry. Moran’s spatial autocorrelation index was used as a measure of tumour phenotypic heterogeneity in medical images. Results: Combination treatment with different doxorubicin formulations resulted in distinct patterns of intratumoural heterogeneity in MRI and in H&E-, Ki-67- and p53-stained images. FDOX or LDOX combined with IMH produced greater deviations from the control group in multimodal spatial organisation of sarcoma-45 than the corresponding drug treatments alone. LDOX + IMH reduced tumour growth by 34% relative to the control group and was associated with distinct histological and immunohistochemical remodelling, including connective tissue replacement and the lowest Ki-67 staining level. The lowest p53 staining levels were observed in the LDOX and LDOX + IMH groups. Conclusions: FDOX and LDOX combined with IMH induced distinct tumour remodelling patterns in sarcoma-45. Multimodal analysis of intratumoural heterogeneity in sarcomas may provide additional quantitative information for assessing treatment response. Full article

Background: Osteosarcoma (OS) is the most common primary malignant bone tumor. Doxorubicin (DOX) is extensively used in OS chemotherapy, yet improving patient outcomes remains challenging. This study investigated the effect of free DOX combined with inductive moderate hyperthermia (IMH) on Saos-2 human OS cells. Methods: Cell viability was assessed by trypan blue exclusion. Flow cytometry analyzed apoptosis, necrosis, and reactive oxygen species (ROS) in cells exposed to control (no treatment), IMH (42 MHz frequency, 500 μT magnetic field induction, 564 V/m electric field strength, 15 W output power, and 30 min duration) alone, DOX (0.06 μg/mL) alone, or DOX combined with IMH. The expression of p14^ARF tumor suppressor and epidermal growth factor receptor (EGFR) was evaluated by immunocytochemistry. Spatial autocorrelation analysis quantified the heterogeneity of p14^ARF and EGFR distributions in acquired images. Results: The half maximal inhibitory concentration (IC₅₀) of DOX in Saos-2 cells had minimal variation between 48 h (0.060 ± 0.01 μg/mL) and 72 h (0.055 ± 0.003 μg/mL). DOX + IMH resulted in a 15% increase in early apoptosis and a 20% elevation in ROS levels compared with DOX alone. Immunocytochemical analysis revealed a 37% increase in p14^ARF and a 32% reduction in EGFR expression following combined treatment in comparison to DOX alone. Image analysis showed that DOX + IMH treatment caused the highest Moran’s index values for p14^ARF and EGFR, reflecting less heterogeneous spatial distributions (p < 0.05). Conclusions: IMH enhanced DOX-induced cytotoxicity in Saos-2 cells by initiating ROS-mediated apoptosis and reducing heterogeneity of cellular responses. Full article

Evaluating intratumor heterogeneity with image texture analysis offers a more sophisticated understanding of sarcoma response to treatment. We examined the effects of inductive moderate hyperthermia (IMH) on sarcoma-45 growth and intratumor heterogeneity across tissue, cellular and molecular levels using magnetic resonance imaging (MRI), ultrasound and histology image analysis. IMH (42 MHz, 20 W) inhibited sarcoma-45 growth kinetics by 34% compared to the untreated control group. T₂-weighted MRI brightness was increased by 42%, reflecting more extensive tumor necrosis, while Young’s modulus increased by 37% due to more pronounced connective tissue replacement in response to IMH. Whereas calculations of Moran’s spatial autocorrelation index revealed distinctions in heterogeneity between tumor core, periphery and capsule regions of interest (ROIs) on MRI, ultrasound and histological examination in the untreated tumor-bearing animals, there was no significant difference between core and periphery after IMH. Exposure to IMH increased overall tumor ROI heterogeneity by 22% on MRI but reduced heterogeneity in the core and periphery on ultrasound and histology images. Ki-67 protein distribution was 25% less heterogeneous on the tumor periphery after IMH. Therefore, this study provides a quantitative characterization of IMH effects on different manifestations of intratumor sarcoma-45 heterogeneity using experimental imaging data. Full article

Despite efforts in osteosarcoma (OS) research, the role of inductive moderate hyperthermia (IMH) in delivering and enhancing the antitumor effect of liposomal doxorubicin formulations (LDOX) remains unresolved. This study investigated the effect of a combination treatment with LDOX and IMH on Saos-2 human OS cells. We compared cell viability using a trypan blue assay, apoptosis and reactive oxygen species (ROS) measured by flow cytometry and pro-apoptotic Bax protein expression examined by immunocytochemistry in response to IMH (42 MHz frequency, 15 W power for 30 min), LDOX (0.4 μg/mL), and LDOX plus IMH. The lower IC₅₀ value of LDOX at 72 h indicated increased accumulation of the drug in the OS cells. LDOX plus IMH resulted in a 61% lower cell viability compared to no treatment. Moreover, IMH potentiated the LDOX action on the Saos-2 cells by promoting ROS production at temperatures of <42 °C. There was a 12% increase in cell populations undergoing early apoptosis with a less heterogeneous distribution of Bax after combination treatment compared to those treated with LDOX (p < 0.05). Therefore, we determined that IMH could enhance LDOX delivery and its antitumor effect via altered membrane permeabilization, ROS generation, and a lower level of visualized Bax heterogeneity in the Saos-2 cells, suggesting the potential translation of these findings into in vivo studies. Full article

The poor outcome of pancreas ductal adenocarcinomas (PDAC) is frequently linked to therapy resistance. Modulated electro-hyperthermia (mEHT) generated by 13.56 MHz capacitive radiofrequency can induce direct tumor damage and promote chemo- and radiotherapy. Here, we tested the effect of mEHT either alone or in combination with radiotherapy using an in vivo model of Panc1, a KRAS and TP53 mutant, radioresistant PDAC cell line. A single mEHT shot of 60 min induced ~50% loss of viable cells and morphological signs of apoptosis including chromatin condensation, nuclear shrinkage and apoptotic bodies. Most mEHT treatment related effects exceeded those of radiotherapy, and these were further amplified after combining the two modalities. Treatment related apoptosis was confirmed by a significantly elevated number of annexin V single-positive and cleaved/activated caspase-3 positive tumor cells, as well as sub-G1-phase tumor cell fractions. mEHT and mEHT+radioterapy caused the moderate accumulation of γH2AX positive nuclear foci, indicating DNA double-strand breaks and upregulation of the cyclin dependent kinase inhibitor p21^waf1 besides the downregulation of Akt signaling. A clonogenic assay revealed that both mono- and combined treatments affected the tumor progenitor/stem cell populations too. In conclusion, mEHT treatment can contribute to tumor growth inhibition and apoptosis induction and resolve radioresistance of Panc1 PDAC cells. Full article

Single-crystal iron oxide nanorings have been proposed as a promising candidate for magnetic hyperthermia application because of their unique shape-induced vortex-domain structure, which supports good colloidal stability and enhanced magnetic properties. However, the synthesis of single crystalline iron oxide has proven to be challenging. In this article, we showed that chemically synthesized multigrain magnetite nanorings disfavor a shape-induced magnetic vortex-domain structure. Our results indicate that the multigrain Fe₃O₄ nanorings with an average outer diameter of ~110 nm and an inner to outer diameter ratio of ~0.5 do not show a shape-induced vortex-domain structure, which was observed in the single-crystal Fe₃O₄ nanorings of similar dimensions. At 300 Ks, multigrain magnetite nanorings showed an effective anisotropy field of 440 Oe, which can be attributed to its high surface area and intraparticle interaction. Both calorimetric and AC loop measurements showed a moderate inductive heating efficiency of multigrain magnetite nanorings of ~300 W/g at 800 Oe. Our results shed light on the magnetic ground states of chemically synthesized multigrain Fe₃O₄ nanorings. Full article