Experimental study of HIFU incomplete ablation on the damage effect and prognosis of rabbit VX2 breast cancer model.

PURPOSE: High-intensity focused ultrasound (HIFU) represents an emerging noninvasive modality for tumor treatment. While biological responses and immunological change associated with incomplete ablation have not been thoroughly investigated. This study aims to evaluate the damage effect of HIFU incomplete ablation via establishing animal model and further explore its possible mechanism to inhibit tumor growth. METHODS: The rabbit VX2 breast cancer model was established and received HIFU treatment with complete ablation (100% tumor volume) and incomplete ablation (about 80% tumor volume) under real-time B-ultrasound monitoring. Histopathological alterations, dynamics of tumor cell apoptosis and proliferation, expression levels of VEGF, MMP-9, IL-2R, TGF-ß1, HSP-70, IL-6, IL-8, and INF-γ, and the presence of circulating tumor cells (CTCs) were evaluated post-HIFU incomplete ablation. RESULTS: For HIFU 80% ablation group, there was an 85.85% reduction in tumor volume 21 days post-intervention. A marked increase in tumor cell apoptosis and a concomitant decrease in proliferation were observed. Notably, distant tumor metastasis rates, CTC counts, and expression levels of VEGF, MMP-9, IL-2R, TGF-ß1, IL-6, and IL-8 were significantly reduced. In contrast, INF-γ and HSP-70 expressions were notably elevated, aligning with findings from the 100% ablation group. CONCLUSIONS: HIFU incomplete ablation, with an 80% tumor ablation rate, induces substantial tumor damage, augments tumor cell apoptosis, and triggers an anti-tumor immune response, curtailing metastasis. These insights may underpin further investigations into the therapeutic implications of HIFU incomplete ablation.

Heat shock protein expression and autophagy after incomplete thermal ablation and their correlation.

OBJECTIVE: To establish a model of incomplete ablation in nude mice with hepatocellular carcinoma (HCC) and to evaluate heat shock protein (HSP) expression and autophagy and their correlation. MATERIALS AND METHODS: In the first stage, 12 nude mice with HCC were randomly divided into two groups (n = 6). A sham puncture operation was performed for one group, and palliative laser ablation was performed for the other group. All mice were sacrificed after 18 h, and HSP expression, autophagy, and apoptosis were assessed. In the second stage, 16 nude mice with HCC were randomly divided into two groups (n = 8). One group was given an HSP90 inhibitor before the operation, and the other group was given dimethyl sulfoxide (DMSO) as a control. HSP expression, autophagy and apoptosis were assessed for the two groups after palliative laser ablation. RESULTS: In the incomplete ablation model, using nude mice with HCC, HSP90, HSP70, and HSP27 expression was up-regulated, Akt and mTOR phosphorylation was enhanced, autophagy was decreased, and apoptosis was increased. After administration of the HSP90 inhibitor, HSP90, P-Akt, and P-mTOR expression was decreased, autophagy was increased, and apoptosis was further increased. CONCLUSION: Autophagy was decreased in the incomplete ablation model and might be inversely correlated with HSP expression. It is suggested that the HSP90/Akt/mTOR pathway is involved in signal transmission between autophagy and HSPs.

RAD21: A Key Transcriptional Regulator in the Development of Residual Liver Cancer.

Objective: Thermal ablation is a commonly used therapy for hepatocellular carcinoma (HCC). Nevertheless, inadequate ablation can lead to the survival of residual HCC, potentially causing rapid progression. The underlying mechanisms for this remain unclear. This study explores the molecular mechanism responsible for the rapid progression of residual HCC. Methods: We established an animal model of inadequate ablation in BALB/c nude mice and identified a key transcriptional regulator through high-throughput sequencing. Subsequently, we conducted further investigations on RAD21. We evaluated the expression and clinical significance of RAD21 in HCC and studied its impact on HCC cell function through various assays, including CCK-8, wound healing, Transwell migration and invasion. In vitro experiments established an incomplete ablation model verifying RAD21 expression and function. Using ChIP-seq, we determined potential molecules regulated by RAD21 and investigated how RAD21 influences residual tumor development. Results: High RAD21 expression in HCC was confirmed and correlated with low tumor cell differentiation, tumor growth, and portal vein thrombosis. Silencing RAD21 inhibited the migration, invasion, and proliferation significantly in liver cancer cells. Patients with high RAD21 levels showed elevated multiple inhibitory immune checkpoint levels and a lower response rate to immune drugs. Heat treatment intensified the malignant behavior of liver cancer cells, resulting in increased migration, invasion, and proliferation. After subjecting it to heat treatment, the results indicated elevated RAD21 levels in HCC. Differentially expressed molecules regulated by RAD21 following incomplete ablation were primarily associated with the VEGF signaling pathway, focal adhesion, angiogenesis, and hepatocyte growth factor receptor signaling pathway etc. Conclusion: The upregulation of RAD21 expression after incomplete ablation may play a crucial role in the rapid development of residual tumors and could serve as a novel therapeutic target.

Integrated manganese (III)-doped nanosystem for optimizing photothermal ablation: Amplifying hyperthermia-induced STING pathway and enhancing antitumor immunity.

Despite the great promise initially demonstrated by photothermal ablation (PTA) therapy, its inability to completely ablate large tumors is problematic, because this has been found to result in residual tumors at ablation margins and bring a relative high rate of subsequent recurrences and metastases. To address this issue, we herein report a smart photothermal nanosystem (PBM) based on FDA-approved Prussian blue (PB) nanoparticles, doped with Mn (III) to suppress the tumor debris left by incomplete ablation. Notably, our study demonstrated that PTA-induced hyperthermia plays a crucial role in initiating the cGAS-STING pathway by generating damaged cytosolic DNA. This PBM nanosystem, which consumes glutathione and continuously releases Mn(II), further amplifies the PTA-induced cGAS-STING pathway in CT26 colon and 4T1 breast tumor models. Moreover, treatment with PBM following PTA boosted the robust immune response in situ and extended to the whole body with a remarkable suppression effect on both local residual and distant tumors. This work, which improves the antitumor efficacy of nonablated areas utilizing hyperthermia-enhanced immune therapy, may therefore provide a promising adjuvant antitumor strategy for the issue of incomplete ablation. STATEMENT OF SIGNIFICANCE: This work discovered, for the first time, that photothermal ablation-induced hyperthermia plays a crucial role in initiating the cGAS-STING pathway. Taking advantage of this finding, we developed a smart photothermal material (PBM) tailored for incomplete tumor ablation. This integrated Mn(III)-doped nanosystem (PBM) demonstrated superior therapeutic benefits due to the thermal ablation process and immune enhancement. As the photothermal ablation-induced cGAS-STING pathway was triggered, the released Mn(III) consumes GSH while continuously transferred to Mn(II), which further amplified STING activation and facilitated a more robust antitumor immunity, thereby remarkably inhibiting both local residual and distant tumors in virtue of the biological changes under thermal ablation.

Factors associated with initial incomplete ablation for benign thyroid nodules after radiofrequency ablation: First results of CEUS evaluation.

OBJECTIVE: To assess the factors associated with initial incomplete ablation (ICA) after radiofrequency ablation for benign thyroid nodules (BTNs). MATERIALS AND METHODS: 69 BTNs (mean volume 6.35±5.66 ml, range 1.00-25.04 ml) confirmed by fine-needle aspiration cytology (FNAC) in fifty-four patients were treated with ultrasound-guided percutaneous radiofrequency ablation (RFA) and the local treatment efficacy was immediately assessed by intra-procedural contrast-enhanced ultrasound (CEUS). The RFA was performed with a bipolar electrode (CelonProSurge 150-T20, output power: 20 W). CEUS was performed with a second generation contrast agent under low acoustic power (i.e. coded phase inversion, CPI). Characteristics of clinical factors, findings on conventional gray-scale ultrasound, color-Doppler ultrasound, and CEUS were evaluated preoperatively. Factors associated with initial ICA and initial ICA patterns on CEUS were assessed. Volume reduction ratios (VRRs) of ICA nodules were compared with those with complete ablation (CA). RESULTS: The RFA procedures were accomplished with a mean ablation time and mean total energy deposition of 11.13±3.39 min (range, 5.38-22.13 min) and 12612±4466 J (range, 6310-26130 J) respectively. CEUS detected initial ICA in 21 of 69 (30.8%) BTNs and 16 (76.2%) of the 21 BTNs with initial ICA achieved CA after additional RFA, leading to a final CA rate of 92.8% (64/69). The factors associated with initial ICA were predominantly solid nodule, nodule close to danger triangle area, nodule close to carotid artery, and peripheral blood flow on color-Doppler ultrasound (all P < 0.05). The mean VRRs of all BTNs were 23.4%, 54.4% and 81.9% at the 1-, 3- and 6-month follow-up, respectively. All BTNs achieved therapeutic success in this series in that all had VRRs of >50% at the 6-month follow-up, among which 7 nodules (10.1%) had VRRs of >90%. There were significant differences in VRRs between ICA nodules and CA nodules at the 3- and 6-month follow-up (all P < 0.05). CONCLUSION: The factors associated with initial ICA after RFA for BTNs were predominantly solid nodules, nodule close to danger triangle area, nodule close to carotid artery, and peripheral blood flow on color-Doppler ultrasound. CEUS assists quick treatment response evaluation and facilitates subsequent additional RFA and final CA of the nodules. Nodules with CA achieve a better outcome in terms of VRR in comparison with those with ICA.