Insufficient radiofrequency ablation promotes the metastasis of residual hepatocellular carcinoma cells via upregulating flotillin proteins

Enhancing the therapeutic impact of sublethal radiofrequency hyperthermia in malignant solid tumor treatment

Radiofrequency ablation (RFA) is an effective alternative to surgery for managing some malignant solid tumors. However, for medium-to-large tumors (>3 cm), tumors adjacent to large blood vessels, and certain irregular tumors, sublethal radiofrequency hyperthermia (RFH) often produces a margin of ablated tumor owing to the "heat-sink" effect. This effect typically leaves behind viable residual tumors at the margin. Several studies have reported that a sublethal RFH can significantly enhance the efficacy of chemotherapy, radiotherapy, immunotherapy, and gene therapy for malignant solid tumors. The possible mechanisms by which RFH enhances these therapies include heat-induced tissue fracturing, increased permeability of the cytoplasmic membrane, exaggerated cellular metabolism, blockade of the repair pathways of radiation-damaged tumor cells, and activation of the heat shock protein pathways. Therefore, RFA in combination with chemotherapy, radiotherapy, immunotherapy, or gene therapy may help reduce the rates of residual and recurrent tumors after RFA of malignant solid tumors.

Neoadjuvant chemo-immunotherapy is improved with a novel pulsed electric field technology in an immune-cold murine model

Chemo-immunotherapy uses combined systemic therapies for resectable and unresectable tumors. This approach is gaining clinical momentum, but survival increases leave considerable room for improvement. A novel form of Pulsed Electric Field (PEF) ablation combines focal tissue destruction with immune activation in preclinical settings. The PEFs induce lethal cell damage without requiring thermal processes, leaving cellular proteins intact. This affords PEF a favorable safety profile, improved antigenicity, and significant immunostimulatory damage-associated molecular pattern release compared to other focal therapies. Preclinical investigations demonstrate a combinatorial benefit of PEF with immunostimulation. This study evaluates whether this proprietary PEF therapy induces an immunostimulatory effect sufficient to augment systemic neoadjuvant chemotherapy and immunotherapy to reverse metastatic disease in an immune-cold murine tumor model. To determine whether PEF improves a neoadjuvant chemo-immunotherapy standard-of-care, partial PEF ablation was delivered to orthotopically inoculated 4T1 metastatic tumors in addition to combinations of cisplatin chemotherapy and/or αPD-1 immunotherapy, followed by resection. In addition, to determine whether PEF combined with chemo-immunotherapy improves local and metastatic response in unresectable populations, partial PEF ablation was added to chemo-immunotherapy in mice that did not receive resection. Blood cytokines and flow cytometry evaluated immune response. Partial PEF ablation generates an immunostimulatory tumor microenvironment, increases systemic immune cell populations, slows tumor growth, and prolongs survival relative to neoadjuvant systemic therapies-alone. These data suggest the addition of this proprietary PEF locoregional therapy may synergize with systemic standard-of-care paradigms to improve outcomes with potential or demonstrated metastatic disease in both resectable and unresectable patient cohorts.

NIO-1, A Novel Inhibitor of OCT1, Enhances the Antitumor Action of Radiofrequency Ablation against Hepatocellular Carcinoma

BACKGROUND

Radiofrequency ablation (RFA) is an important treatment strategy for patients with advanced hepatocellular carcinoma (HCC). However, its therapeutic effect is unsatisfactory and recurrence often occurs after RFA treatment. The octamer-binding transcription factor OCT1 is a novel tumour-promoting factor and an ideal target for HCC therapy.

OBJECTIVE

This study aimed to expand the understanding of HCC regulation by OCT1.

METHODS

The expression levels of the target genes were examined using qPCR. The inhibitory effects of a novel inhibitor of OCT1 (NIO-1) on HCC cells and OCT1 activation were examined using Chromatin immunoprecipitation or cell survival assays. RFA was performed in a subcutaneous tumour model of nude mice.

RESULTS

Patients with high OCT1 expression in the tumour tissue had a poor prognosis after RFA treatment (n = 81). The NIO-1 showed antitumor activity against HCC cells and downregulated the expression of the downstream genes of OCT1 in HCC cells, including those associated with cell proliferation (matrix metalloproteinase-3) and epithelial-mesenchymal transition-related factors (Snail, Twist, N-cadherin, and vimentin). In a subcutaneous murine model of HCC, NIO-1 enhanced the effect of RFA treatment on HCC tissues (n = 8 for NIO-1 and n = 10 for NIO-1 + RFA).

CONCLUSION

This study demonstrated the clinical importance of OCT1 expression in HCC for the first time. Our findings also revealed that NIO-1 aids RFA therapy by targeting OCT1.

Interventional Oncolytic Immunotherapy with LTX-315 for Residual Tumor after Incomplete Radiofrequency Ablation of Liver Cancer

Objective: To investigate the feasibility of interventional oncolytic immunotherapy with LTX-315 for residual tumors after incomplete radiofrequency ablation (iRFA) of VX2 liver tumors in a rabbit model. Methods: For in vitro experiments, VX2 tumor cells were treated with: (1) phosphate buffered saline, (2) radiofrequency hyperthermia (RFH), (3) LTX-315, and (4) RFH plus LTX-315. The residual tumors after iRFA of VX2 liver tumors were treated with: (1) phosphate buffered saline served as control, (2) 2 mg LTX-315, and (3) 4 mg LTX-315. MTS assay, fluorescence microscopy, and flow cytometry were used to compare cell viabilities and apoptosis among different groups. Ultrasound imaging was used to follow up the tumor growth, which were correlated with the optical imaging and subsequent histology. Results: For in vitro experiments, compared with the other three groups, MTS assay demonstrated the lowest cell viability, fluorescence microscopy showed the least survival cells, and apoptosis analysis revealed the highest percentage of apoptosis cells in the combination treatment groups (p < 0.001). For in vivo experiments, ultrasound imaging showed the smallest tumor volume in the group with 4 mg LTX-315 therapy compared with the other two groups (p < 0.001). The optical imaging and histopathological analysis showed complete necrosis of the tumors in the group with 4 mg LTX-315 therapy. A significant increase of CD8+ T cells and HSP70 and a significant decrease of Tregs were observed in residual tumors in the group with 2 mg LTX-315 therapy compared with the control group (p < 0.001). Conclusion: Interventional oncolytic immunotherapy with LTX-315 for residual tumors after iRFA of liver cancer is feasible, which may open up new avenues to prevent residual tumors after RFA of intermediate-to-large liver cancers.

Impact of endobiliary radiofrequency ablation on biliary drainage in patients with malignant biliary strictures treated with uncovered self-expandable metal stents: a randomized controlled multicenter trial

BACKGROUND AND AIMS

Endobiliary radiofrequency ablation (RFA), usually combined with endoscopic stent insertion, is a simple procedure with the potential to improve stent patency and patient survival for malignant biliary obstruction. We conducted this randomized multicenter trial to evaluate the impact of RFA on stent patency.

METHODS

Eighty-six patients with malignant biliary obstruction and nonresectable tumors (pancreatic carcinoma, cholangiocarcinoma, or metastases) were included and randomly assigned to receive a self-expandable metal stent (SEMS) only (n = 44) or RFA followed by SEMS insertion (RFA+SEMS, n = 42). The primary outcome measure was stent patency after 3 and 6 months; secondary outcome measures were patient survival and early adverse events within 30 days.

RESULTS

Technical success rates for RFA and stent insertion were 100% and 98.8%, respectively. Stent patency after 3 and 6 months did not differ significantly between groups (RFA+SEMS group, 73.1% and 33.3%, respectively; SEMS-only group, 81.8% and 52.4%, respectively; P = .6). Similarly, the addition of RFA did not impact overall survival (hazard ratio, .72; P = .389 for RFA+SEMS). The adverse event rate in the RFA+SEMS group was 10.5% compared with 2.3% in the SEMS-only group, without a statistically significant difference (P = .18).

CONCLUSIONS

RFA as an addition to SEMS implantation had no positive impact on patency rate or survival. (Clinical trial registration number: DRKS00018993.).

Combinatory local ablation and immunotherapies for hepatocellular carcinoma: Rationale, efficacy, and perspective

Hepatocellular carcinoma (HCC) is the leading cause of cancer-related death worldwide. Local ablation, such as radiofrequency ablation, microwave ablation, cryoablation and irreversible electroporation, etc., are well established in elimination and control of HCC. However, high recurrence rate after local ablation remains the biggest challenge for HCC management. Novel and effective therapeutic strategies to improve long-term survival are urgently needed. Accumulating studies have reported the role of ablation in modulating the tumor signaling pathway and the immune microenvironment to both eliminate residual/metastatic tumor and promote tumor progression. Ablation has been shown to elicit tumor-specific immune responses by inducing massive cell death and releasing tumor antigen. Immunotherapies that unleash the immune system have the potential to enhance the anti-tumor immunity induced by ablation. Multiple combinatory strategies have been explored in preclinical and clinical studies. In this review, we comprehensively summarize the latest progress on different mechanisms underlying the effects of ablation on tumor cells and tumor microenvironment. We further analyze the clinical trials testing the combination of ablation and immunotherapies, and discuss the possible role of immunomodulation to boost the anti-tumor effects of ablation and prevent HCC recurrence.

Progression of hepatocellular carcinoma after radiofrequency ablation: Current status of research

Hepatocellular carcinoma (HCC) remains an important disease for health care systems in view of its high morbidity, mortality, and increasing incidence worldwide. Radiofrequency ablation (RFA) is preferred to surgery as a local treatment for HCC because it is safer, less traumatic, less painful, better tolerated, causes fewer adverse reactions, and allows more rapid postoperative recovery. The biggest shortcoming of RFA when used to treat HCC is the high incidence of residual tumor, which is often attributed to the vascular thermal deposition effect, the wide infiltration zone of peripheral venules, and the distance between satellite foci and the main focus of the cancer. Recurrence and progression of the residual tumor is the most important determinant of the prognosis. Therefore, it is important to be aware of the risk of recurrence and to improve the efficacy of RFA. This review summarizes the relevant literature and the possible mechanisms involved in progression of HCC after RFA. Current studies have demonstrated that multimodal treatments which RFA combined with other anti-cancer approaches can prevent progression of HCC after RFA.

HIF-2α regulates proliferation, invasion, and metastasis of hepatocellular carcinoma cells via VEGF/Notch1 signaling axis after insufficient radiofrequency ablation

Background and Aims

Although insufficient radiofrequency ablation (RFA) promotes the recurrence and metastasis of liver cancer, the underlying mechanism remains unclear. This study aimed to investigate the role and mechanism of HIF-2α in hepatocellular carcinoma cells (HCCs) after Insufficient RFA.

Methods

We established a model of insufficient RFA in MHCC97H hepatoma cells and screened for stable sublines. We inhibited HIF-2α expression in the Insufficient RFA group using PT2385 and assessed the resulting changes in proliferation and biological function of HCCs. Cell viability and proliferation were detected by the MTT method, and scratch and Transwell chamber invasion tests detected migration and invasion abilities of HCCs. The mRNA and protein expression levels of VEGF, HIF-2α, and Notch1 were detected using qPCR, immunofluorescence, and western blotting.

Results

Compared with normal HCCs without RFA treatment, insufficient RFA enhanced the proliferation and invasion abilities of hepatocellular carcinoma subline MHCC97H (P < 0.001), as well as their migration ability (P = 0.046). The HIF-2α-specific inhibitor PT2385 downregulated the migration (P = 0.009) and invasion (P < 0.001) of MHCC97H cells but did not affect cell proliferation (P > 0.05). Insufficient ablation increased the mRNA and protein expression of VEGF, HIF-2α, and Notch1 in HCCs, whereas inhibition of HIF-2α reversed these changes.

Conclusions

Insufficient RFA increases the proliferation, migration, and invasion of HCCs via the HIF-2α/VEGF/Notch1 signaling axis; HIF-2α is a potential target for novel treatments of HCC after insufficient RFA.

Investigation of the efficacy and safety of cryoablation and intra-arterial PD-1 inhibitor in patients with advanced disease not responding to checkpoint inhibitors: An exploratory study

Objective

To explore the effectiveness of cryoablation combined with arterial perfusion with programmed cell death protein 1 inhibitors in overcoming immune resistance in advanced solid cancers.

Methods

In this pilot retrospective study, nine patients with solid cancers were treated with tumour cryoablation and arterial perfusion with programmed cell death protein 1 inhibitors, which had previously proven ineffective. The CIBERSORT software was used to estimate the levels of tumour-infiltrating immune cells in the challenged tumour. Changes in the levels of circulating T cells were assessed using flow cytometry. The primary endpoints were disease control and objective response rates, and the secondary endpoint was safety.

Results

The nine patients with advanced solid tumours received cryoablation combined with arterial perfusion with programmed cell death protein 1 inhibitors between June and December 2021. The median follow-up time was 5.8 months. We recorded an objective response rate in two patients (22.22%). The best overall responses were partial responses in two patients (22.22%) and one case (11.11%) of stable disease, while six patients (66.67%) presented progressive disease. However, the median overall survival time was not reached. The median progression-free survival was 2.4 months. Treatment-related severe adverse events included one case of abdominal infection and one case of upper gastrointestinal bleeding, which were cured after the intervention. The CIBERSORT software confirmed the importance of cryoablation in regulating tumour-infiltrating immune cells. Thus, macrophage polarisation from the M2 to the M1 phenotype in the challenged tumour and a gradual increase in the levels of circulating CD4⁺ T cells were observed after administration of the combination therapy.

Conclusion

Cryoablation combined with arterial perfusion with programmed cell death protein 1 inhibitors has the potential efficacy and safety to overcome immune resistance in patients with advanced solid cancers. The combination therapy leads to macrophage polarisation from the M2 to the M1 phenotype in the challenged tumour to enhance antitumour immunity.

The lipid rafts in cancer stem cell: a target to eradicate cancer

Cancer stem cells (CSCs) are a subpopulation of cancer cells with stem cell properties that sustain cancers, which may be responsible for cancer metastasis or recurrence. Lipid rafts are cholesterol- and sphingolipid-enriched microdomains in the plasma membrane that mediate various intracellular signaling. The occurrence and progression of cancer are closely related to lipid rafts. Emerging evidence indicates that lipid raft levels are significantly enriched in CSCs compared to cancer cells and that most CSC markers such as CD24, CD44, and CD133 are located in lipid rafts. Furthermore, lipid rafts play an essential role in CSCs, specifically in CSC self-renewal, epithelial-mesenchymal transition, drug resistance, and CSC niche. Therefore, lipid rafts are critical regulatory platforms for CSCs and promising therapeutic targets for cancer therapy.

Recent Perspectives on the Mechanism of Recurrence After Ablation of Hepatocellular Carcinoma: A Mini-Review

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors. Hepatectomy, liver transplantation, and ablation are the three radical treatments for early-stage hepatocellular carcinoma (ESHCC), but not all patients are fit for or can tolerate surgery; moreover, liver donors are limited. Therefore, ablation plays an important role in the treatment of ESHCC. However, some studies have shown that ablation has a higher local recurrence (LR) rate than hepatectomy and liver transplantation. The specific mechanism is unknown. The latest perspectives on the mechanism of recurrence after ablation of HCC were described and summarized. In this review, we discussed the possible mechanisms of recurrence after ablation of HCC, including epithelial–mesenchymal transition (EMT), activating autophagy, changes in non-coding RNA, and changes in the tumor microenvironment. A systematic and comprehensive understanding of the mechanism will contribute to the research and development of related treatment, combined with ablation to improve the therapeutic effect in patients with ESHCC.

Radiofrequency ablation in the treatment of hepatocellular carcinoma

OBJECTIVE

The purpose of this article is to discuss the use, comparative efficacy, and research progress of radiofrequency ablation (RFA), alone or in combination with other therapies, for the treatment of hepatocellular carcinoma (HCC).

METHOD

To search and summarize the basic and clinical studies of RFA in recent years.

RESULTS

RFA is one of the radical treatment methods listed in the guidelines for the diagnosis and treatment of HCC. It has the characteristics of being minimally invasive and safe and can obtain good local tumor control, and it can improve the local immune ability, improve the tumor microenvironment and enhance the efficacy of chemotherapy drugs. It is commonly used for HCC treatment before liver transplantation and combined ALPPS and hepatectomy for HCC. In addition, the technology of RFA is constantly developing. The birth of noninvasive, no-touch RFA technology and equipment and the precise RFA concept have improved the therapeutic effect of RFA.

CONCLUSION

RFA has good local tumor control ability, is minimally invasive, is safe and has other beneficial characteristics. It plays an increasingly important role in the comprehensive treatment strategy of HCC. Whether RFA alone or combined with other technologies expands the surgical indications of patients with HCC and provides more benefits for HCC patients needs to be determined.

Circular BANP knockdown inhibits the malignant progression of residual hepatocellular carcinoma after insufficient radiofrequency ablation

BACKGROUND

Circular RNAs (circRNAs) are endogenous non-coding RNAs, some of which have pathological roles. The current study aimed to explore the role of circRNA BTG3-associated nuclear protein (circ-BANP) binding with let-7f-5p and its regulation of the toll-like receptor 4 (TLR4)/signal transducer and activator of transcription 3 (STAT3) signaling pathway in residual hepatocellular carcinoma (HCC) after insufficient radiofrequency ablation (RFA).

METHODS

Circ-BANP, let-7f-5p, and TLR4 expressions in HCC samples were assessed using reverse transcription- quantitative polymerase chain reaction (RT-qPCR) and Western blotting. Bioinformatics prediction, RNA pull-down assay, and dual luciferase reporter gene assay were used to analyze the relationships among circ-BANP, let-7f-5p, and TLR4. Huh7 cells were used to generate an in vitro model of residual HCC, defined as Huh7-H cells, which were transfected with either a plasmid or the sequence of circ-BANP, let-7f-5p, or TLR4. Expression of circ-BANP, let-7f-5p, and TLR4 mRNA was determined by RT-qPCR. TLR4, STAT3, p-STAT3, vascular endothelial growth factor A, vascular endothelial growth factor receptor-2, and epithelial-mesenchymal transformation (EMT)-related factors proteins were determined by Western blotting. Cell proliferation was determined by cell counting kit-8 and 5-Ethynyl-2'-deoxyuridine (EdU) assay and cell migration and invasion by Transwell assay. Animal studies were performed by inducing xenograft tumors in nude mice.

RESULTS

Circ-BANP and TLR4 mRNAs were upregulated in HCC tissues (the fold change for circ-BANP was 1.958 and that for TLR4 was 1.736 relative to para-tumors) and expression further increased following insufficient RFA (fold change for circ- BANP was 2.407 and that of TLR4 was 2.224 relative to para-tumors). Expression of let-7f-5p showed an opposite tendency (fold change for let-7f-5p in HCC tissues was 0.491 and that in tumors after insufficient RFA was 0.300 relative to para-tumors). Competitive binding of circ-BANP to let-7f-5p was demonstrated and TLR4 was identified as a target of let-7f-5p (P < 0.01). Knockdown of circ-BANP or elevation of let-7f-5p expression inhibited the TLR4/STAT3 signaling pathway, proliferation, invasion, migration, angiogenesis, and EMT in Huh7 and Huh7-H cells (P < 0.01). The effects induced by circ-BANP knockdown were reversed by let-7f-5p inhibition. Overexpression of TLR4 reversed the impact of let-7f-5p upregulation on the cells (P < 0.01). Silencing of circ-BANP inhibited the in vivo growth of residual HCC cells after insufficient RFA (P < 0.01).

CONCLUSIONS

Knockdown of circ-BANP upregulated let-7f-5p to inhibit proliferation, migration, and EMT formation in residual HCC remaining after insufficient RFA. Effects occur via regulation of the TLR4/STAT3 signaling pathway.

The study of direct and indirect effects of radiofrequency ablation on tumor microenvironment in liver tumor animal model

Background

Direct and indirect effects of radiofrequency ablation (RFA) on tumor microenvironment of the liver tumor have been noted, which was reported to be related to a variety of tyrosine protein kinase or cytokinetic pathway, but have not been thoroughly investigated and conclusive.

Purpose

To elucidate direct and indirect effects of RFA on tumor microenvironment in the liver tumor model, and to explore the role of the specific inhibitor in tumor growth by targeting the key pathway of RFA.

Materials and methods

One hundred and ten mice with H22 liver tumor were used in animal experiments. Eighty-four mice were randomized into three groups: control, direct RFA and indirect RFA (a block slide was inside the middle of the tumor). The growth rate of the residual tumor after RFA was calculated (n = 8 each group) and the pathologic changes at different time points (6 h, 24 h, 72 h and 7d after RFA) were evaluated (n = 5 in each subgroup). After semi-quantitative analysis of the pathological staining, the most significant marker after RFA was selected. Then, the specific inhibitor (PHA) was applied with RFA and the tumor growth and pathological changes were evaluated and compared with RFA alone. The Kruskal-Wallis test was used for evaluating the significance of different treatments in the pathological positive rate of specific markers in tumor. The two-way analysis of variance was used to determine the significance of treatment in tumor growth or body weight.

Results

The growth rate of the residual tumor in the direct RFA group was faster than the indirect RFA group (P = 0.026). The pathological analysis showed the expression of HSP70 (73 ± 13% vs 27 ± 9% at 24 h, P < 0.001), SMA (70 ± 18% vs 18 ± 7% at 6 h, P < 0.001) and Ki-67 (51 ± 11% vs 33 ± 14% at 7d, P < 0.001) in the direct RFA group was higher than those in the indirect RFA group after RFA. On the other hand, the expression of c-Met (38 ± 11% vs 28 ± 9% at 24 h, P = 0.01), IL-6 (41 ± 10% vs 25 ± 9% at 24 h, P < 0.001) and HIF-α (48 ± 10% vs 28 ± 8% at 24 h, P < 0.001) in the indirect RFA group was higher than those in the direct RFA group. And the expression of c-Met increased mostly in both direct and indirect RFA group compared to the baseline (53 and 65% at 72 h). Then the specific inhibitor of c-Met-PHA was applied with RFA. The growth rate of the tumor was significantly slower in the RFA + PHA group than the RFA alone group (1112.9 ± 465.6 mm³ vs 2162.7 ± 911.1 mm³ at day 16, P = 0.02).

Conclusion

Direct and indirect effects of RFA on tumor microenvironment changed at different time points and resulted in increased residual tumor growth in the animal model. It can be potentially neutralized with specific inhibitor of related pathways, such as tyrosine-protein kinase c-Met.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09730-x.

A Novel Small Molecular Inhibitor of DNMT1 Enhances the Antitumor Effect of Radiofrequency Ablation in Lung Squamous Cell Carcinoma Cells

Radiofrequency ablation (RFA) is a relatively new and effective therapeutic strategy for treating lung squamous cell carcinomas (LSCCs). However, RFA is rarely used in the clinic for LSCC which still suffers from a lack of effective comprehensive treatment strategies. In the present work, we investigate iDNMT, a novel small molecular inhibitor of DNMT1 with a unique structure. In clinical LSCC specimens, endogenous DNMT1 was positively associated with methylation rates of miR-27-3p's promoter. Moreover, endogenous DNMT1 was negatively correlated with miR-27-3p expression which targets PSEN-1, the catalytic subunit of γ-secretase, which mediates the cleavage and activation of the Notch pathway. We found that DNMT1 increased activation of the Notch pathway in clinical LSCC samples while downregulating miR-27-3p expression and hypermethylation of miR-27-3p's promoter. In addition of inhibiting activation of the Notch pathway by repressing methylation of the miR-27-3p promoter, treatment of LSCC cells with iDNMT1 also enhanced the sensitivity of LSCC tumor tissues to RFA treatment. These data suggest that iDNMT-induced inhibition of DNMT-1 enhances miR-27-3p expression in LSCC to inhibit activation of the Notch pathway. Furthermore, the combination of iDNMT and RFA may be a promising therapeutic strategy for LSCC.

An Overview of Hepatocellular Carcinoma After Insufficient Radiofrequency Ablation

Radiofrequency ablation (RFA) is a commonly used treatment for hepatocellular carcinoma (HCC), however, various complex conditions in clinical practice may lead to insufficient radiofrequency ablation (IRFA), allowing residual HCC to survive. In clinical practice and laboratory models, IRFA plays an important role in rapid tumor progression. Therefore, targeting the residual HCC and avoiding IRFA were worthwhile methods. A deeper understanding of IRFA is required; IRFA contributes to the improvement of proliferative activity, migration rates, and invasive capacity, and this may be due to the involvement of multiple complex processes or proteins, including epithelial mesenchymal transitions (EMTs), cancer stem cells (CSCs), autophagy, heat shock proteins (HSPs), changes of non-tumor cells and extracellular matrix, altered immune microenvironment, hypoxia-inducible factors (HIFs), growth factors, epigenetic alterations, and metabolic reprogramming. We focus on the processes of the above mechanisms and possible therapeutic approach, with a review of the literature. Additionally, we recapitulated the construction methods of various experimental models of IRFA (in vivo and in vitro).

Sublethal heat treatment promotes breast cancer metastasis and its molecular mechanism revealed by quantitative proteomic analysis

Radiofrequency ablation (RFA) is a frequently used thermal ablation technique for breast tumors. The study aimed to identify the effect of sublethal heat treatment on biological function of breast cancer cells and reveal its potential molecular mechanism. The expression profile of dysregulated proteins in sublethal heat treated breast cancer cells was analyzed by quantitative proteomic analysis. The differentially expressed proteins in the sublethal heat treated breast cancer were identified. The potential biological functions of these proteins were evaluated. The proliferation and invasion ability of breast cancer cells were enhanced after sublethal heat treatment. The expression profile of proteins in sublethal heat treated breast cancer cells was abundant, and most of which were newly discovered. A total of 206 differentially expressed proteins were identified. Among them, 101 proteins were downregulated while 105 proteins were upregulated. GO and KEGG analysis indicated that various systems were involved in the process of sublethal heat treatment including cancer, immune system, et al. Immunohistochemistry staining showed that the expression of Heat shock protein 1B, NOB1 and CRIP1 was highly expressed while the expression of BCLAF1 was lower in sublethal heat treated group. The proliferation and invasion ability of breast cancer cells were enhanced after sublethal heat treatment. Sublethal heat treatment caused gene alterations in cancer and immune system. Heat shock protein 1B, NOB1 and CRIP1 were upregulated while BCLAF1 was downregulated in breast cancer after sublethal heat treatment.

Flotillin-1 promotes progression and dampens chemosensitivity to cisplatin in gastric cancer via ERK and AKT signaling pathways

BACKGROUND

Several past studies have reported the overexpression of Flotillin-1 in a variety of cancer types. Cisplatin is a chemotherapeutic drug commonly used for cancer treatment. The present study investigated the role of Flotillin-1 in the progression of GC and assessed whether it assists in the chemical sensitization of GC cells toward cisplatin.

METHOD

The expression of Flotillin-1 was detected both in human gastric mucosal cells and GC cells. Next, siRNA and shRNA were used to construct a stable cell line expressing low levels of Flotillin-1. Furthermore, the Cell Counting Kit 8 (CCK-8), flow cytometry, and transwell assays were employed to detect the impact of Flotillin-1 on GC cells. In addition, a nude mouse model of human GC was used to verify the knockdown of Flotillin-1 to increase the sensitivity of GC cells to cisplatin.

RESULTS

Flotillin-1 was overexpressed in GC cells when compared to that in human gastric mucosal cells. The results for in vitro and vivo assays revealed that the knockdown of Flotillin-1 could significantly inhibit the proliferation of GC cells and increased the sensitivity of GC cells to cisplatin via the regulation of the protein kinase B (AKT) and extracellular signal-regulated kinase (ERK) signaling pathway.

CONCLUSION

Flotillin-1 might be used as a molecular marker for GC diagnosis and could be explored as a potential new target for the treatment of GC.

Augmented EPR effect post IRFA to enhance the therapeutic efficacy of arsenic loaded ZIF-8 nanoparticles on residual HCC progression

BACKGROUND

Insufficient radiofrequency ablation (IRFA) can promote the local recurrence and distal metastasis of residual hepatocellular carcinoma (HCC), which makes clinical treatment extremely challenging. In this study, the malignant transition of residual tumors after IRFA was explored. Then, arsenic-loaded zeolitic imidazolate framework-8 nanoparticles (As@ZIF-8 NPs) were constructed, and their therapeutic effect on residual tumors was studied.

RESULTS

Our data showed that IRFA can dramatically promote the proliferation, induce the metastasis, activate the epithelial-mesenchymal transition (EMT) and accelerate the angiogenesis of residual tumors. Interestingly, we found, for the first time, that extensive angiogenesis after IRFA can augment the enhanced permeability and retention (EPR) effect and enhance the enrichment of ZIF-8 nanocarriers in residual tumors. Encouraged by this unique finding, we successfully prepared As@ZIF-8 NPs with good biocompatibility and confirmed that they were more effective than free arsenic trioxide (ATO) in sublethal heat-induced cell proliferation suppression, apoptosis induction, cell migration and invasion inhibition, and EMT reversal in vitro. Furthermore, compared with free ATO, As@ZIF-8 NPs exhibited remarkably increased therapeutic effects by repressing residual tumor growth and metastasis in vivo.

CONCLUSIONS

This work provides a new paradigm for the treatment of residual HCC after IRFA.

Circular BANP knockdown inhibits the malignant progression of residual hepatocellular carcinoma after insufficient radiofrequency ablation

BACKGROUND

Circular RNAs (circRNAs) are endogenous non-coding RNAs, some of which have pathological roles. The current study aimed to explore the role of circRNA BTG3-associated nuclear protein (circ-BANP) binding with let-7f-5p and its regulation of the toll-like receptor 4 (TLR4)/signal transducer and activator of transcription 3 (STAT3) signaling pathway in residual hepatocellular carcinoma (HCC) after insufficient radiofrequency ablation (RFA).

METHODS

Circ-BANP, let-7f-5p, and TLR4 expressions in HCC samples were assessed using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blotting. Bioinformatics prediction, RNA pull-down assay, and dual luciferase reporter gene assay were used to analyze the relationships among circ-BANP, let-7f-5p, and TLR4. Huh7 cells were used to generate an in vitro model of residual HCC, defined as Huh7-H cells, which were transfected with either a plasmid or the sequence of circ-BANP, let-7f-5p, or TLR4. Expression of circ-BANP, let-7f-5p, and TLR4 mRNA was determined by RT-qPCR. TLR4, STAT3, p-STAT3, vascular endothelial growth factor A, vascular endothelial growth factor receptor-2, and epithelial-mesenchymal transformation (EMT)-related factors proteins were determined by Western blotting. Cell proliferation was determined by cell counting kit-8 and 5-Ethynyl-2'-deoxyuridine (EdU) assay and cell migration and invasion by Transwell assay. Animal studies were performed by inducing xenograft tumors in nude mice.

RESULTS

Circ-BANP and TLR4 mRNAs were upregulated in HCC tissues (the fold change for circ-BANP was 1.958 and that for TLR4 was 1.736 relative to para-tumors) and expression further increased following insufficient RFA (fold change for circ-BANP was 2.407 and that of TLR4 was 2.224 relative to para-tumors). Expression of let-7f-5p showed an opposite tendency (fold change for let-7f-5p in HCC tissues was 0.491 and that in tumors after insufficient RFA was 0.300 relative to para-tumors). Competitive binding of circ-BANP to let-7f-5p was demonstrated and TLR4 was identified as a target of let-7f-5p (P < 0.01). Knockdown of circ-BANP or elevation of let-7f-5p expression inhibited the TLR4/STAT3 signaling pathway, proliferation, invasion, migration, angiogenesis, and EMT in Huh7 and Huh7-H cells (P < 0.01). The effects induced by circ-BANP knockdown were reversed by let-7f-5p inhibition. Overexpression of TLR4 reversed the impact of let-7f-5p upregulation on the cells (P < 0.01). Silencing of circ-BANP inhibited the in vivo growth of residual HCC cells after insufficient RFA (P < 0.01).

CONCLUSIONS

Knockdown of circ-BANP upregulated let-7f-5p to inhibit proliferation, migration, and EMT formation in residual HCC remaining after insufficient RFA. Effects occur via regulation of the TLR4/STAT3 signaling pathway.

Combination of Ablation and Immunotherapy for Hepatocellular Carcinoma: Where We Are and Where to Go

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide and is increasing in incidence. Local ablative therapy plays a leading role in HCC treatment. Radiofrequency (RFA) is one of the first-line therapies for early local ablation. Other local ablation techniques (e.g., microwave ablation, cryoablation, irreversible electroporation, phototherapy.) have been extensively explored in clinical trials or cell/animal studies but have not yet been established as a standard treatment or applied clinically. On the one hand, single treatment may not meet the needs. On the other hand, ablative therapy can stimulate local and systemic immune effects. The combination strategy of immunotherapy and ablation is reasonable. In this review, we briefly summarized the current status and progress of ablation and immunotherapy for HCC. The immune effects of local ablation and the strategies of combination therapy, especially synergistic strategies based on biomedical materials, were discussed. This review is hoped to provide references for future researches on ablative immunotherapy to arrive to a promising new era of HCC treatment.

Inhibition of SREBP-1 Activation by a Novel Small-Molecule Inhibitor Enhances the Sensitivity of Hepatocellular Carcinoma Tissue to Radiofrequency Ablation

Radiofrequency ablation (RFA) is an important strategy for treatment of advanced hepatocellular carcinoma (HCC). However, the prognostic indicators of RFA therapy are not known, and there are few strategies for RFA sensitization. The transcription factor sterol regulatory element binding protein 1 (SREBP)-1 regulates fatty-acid synthesis but also promotes the proliferation or metastasis of HCC cells. Here, the clinical importance of SREBP-1 and potential application of knockdown of SREBP-1 expression in RFA of advanced HCC was elucidated. In patients with advanced HCC receiving RFA, a high level of endogenous SREBP-1 expression correlated to poor survival. Inhibition of SREBP-1 activation using a novel small-molecule inhibitor, SI-1, not only inhibited the aerobic glycolysis of HCC cells, it also enhanced the antitumor effects of RFA on xenograft tumors. Overall, our results: (i) revealed the correlation between SREBP-1 and HCC severity; (ii) indicated that inhibition of SREBP-1 activation could be a promising approach for treatment of advanced HCC.

lncENST Suppress the Warburg Effect Regulating the Tumor Progress by the Nkx2-5/ErbB2 Axis in Hepatocellular Carcinoma

The therapeutic efficacy of radiofrequency ablation (RFA) against liver cancer is often limited by proliferation and metastasis of residual tumor cells. These phenomena are closely associated with the Warburg effect, wherein ErbB2 is activated. While RFA inhibits the Warburg effect of residual tumor cells at the early stage, the specific mechanisms remain unclear. We explored the regulatory relationship between the long noncoding RNA ENST00000570843.1 (lncENST) and ErbB2 using lentiviral transfection of lncENST and ErbB2 overexpression/interference vectors in in vitro and in vivo models of hepatocellular carcinoma in the presence of sublethal heat at 50°C. ErbB2-mediated Warburg effect was suppressed by lncENST, as manifested by reduced glucose uptake and lactic acid production in SMMC-7721 cells. lncENST also increased tumor apoptosis and inhibited tumor progression in nude Balb/c mice for up to 28 days after RFA. Additionally, we predicted through bioinformatic analysis that the promoter of ErbB2 binds to the transcription factor Nkx2-5, resulting in a negative regulatory effect. This speculation was confirmed by chromatin immunoprecipitation of the Nkx2-5 protein and ErbB2, indicating that ErbB2 transcription was curbed by Nkx2-5. We propose that lncENST downplays the Warburg effect in residual tumor cells by downregulating ErbB2 via Nkx2-5 activation. This study is aimed at providing molecular targets that can prevent residual tumor cell proliferation after RFA, with clinical significance in hepatocellular carcinoma treatment.

Optimal application of stereotactic body radiotherapy and radiofrequency ablation treatment for different multifocal hepatocellular carcinoma lesions in patients with Barcelona Clinic Liver Cancer stage A4-B1: a pilot study

BACKGROUND

In clinical practice, many hepatocellular carcinoma (HCC) patients in Barcelona Clinical Liver Cancer (BCLC) stage A4-B1 cannot receive the curative treatments of liver transplantation, resection, and radiofrequency ablation (RFA), which are the recommended options according to liver cancer guidelines. Our aim is to study the feasibility of RFA and stereotactic body radiotherapy (SBRT) as a curative treatment for different multifocal HCCs in BCLC stage A4-B1 patients.

METHODS

From September 2014 to August 2019, 39 multifocal HCC lesions (median diameter: 16.6 mm) from 15 patients (median age: 73 years) were retrospectively selected. Among them, 23 were treated by RFA and the other 16 by SBRT because of predictable insufficiency and/or risk related to RFA performance. The indicators for evaluating this novel therapy were the tumor response, prognosis (recurrence and survival), and adverse effects (deterioration of laboratory test values and severe complications).

RESULTS

The median follow-up duration was 31.3 months (range: 15.1-71.9 months). The total patients with a one-year complete response, stable disease, or disease progression were 11, 1, and 3, respectively. In total, 8 and 2 patients had confronted intrahepatic or local recurrence, respectively. The one-year progression-free survival rate and local control rate were 80% (12/15 patients) and 97.4% (38/39 lesions), respectively. The median time to progression was 20.1 (2.8-45.1) months. The one- and two-year survival rates were 100 and 88.9%, respectively. In up to five months' observation, no patient showed severe complications. Seven, four, and two patients had slight changes in their white blood cells, platelet count, or albumin-bilirubin grade, respectively.

CONCLUSIONS

For patients with BCLC stage A4-B1, RFA and SBRT treatment for different multifocal HCCs may be a potential option because of the favorable prognosis and safety. However, before its application in clinical practice, prospective, controlled, large-scale studies are needed to further confirm our conclusions.

Wnt Signaling Pathway Is among the Drivers of Liver Metastasis

Liver metastasis, originating either from a primary liver or other cancer types, represent a large cancer-related burden. Therefore, studies that add to better understanding of its molecular basis are needed. Herein, the role of the Wnt signaling pathway in liver metastasis is outlined. Its role in hepatocellular carcinoma (HCC) epithelial-mesenchymal transition (EMT), motility, migration, metastasis formation, and other steps of the metastatic cascade are presented. Additionally, the roles of the Wnt signaling pathway in the liver metastasis formation of colorectal, breast, gastric, lung, melanoma, pancreatic, and prostate cancer are explored. The special emphasis is given to the role of the Wnt signaling pathway in the communication between the many of the components of the primary and secondary cancer microenvironment that contribute to the metastatic outgrowth in the liver. The data presented herein are a review of the most recent publications and advances in the field that add to the idea that the Wnt pathway is among the drivers of liver metastasis and that its targeting could potentially relieve liver metastasis–related complications.

Value of 18F-FDG PET/MRI in the early evaluation of treatment response following radiofrequency ablation of liver cancer in a rabbit model

PURPOSE

To test the hypothesis that ¹⁸F-fluorodeoxyglucose positron emission tomography and MRI (18F-FDG PET/MRI) can detect early residual tumor following radiofrequency ablation (RFA) of liver cancer using a VX2 tumor model.

METHODS

Twenty-four rabbits with VX2 liver tumors were randomly divided into three groups (n = 8/group): group 1 without RFA treatment, group 2 with complete ablation, and group 3 with partial ablation. ¹⁸F-FDG PET/MRI scan was obtained in three animal groups within 2 hours post-RFA. The maximum standardized uptake value (SUVmax) of non-treated liver tumor, benign peri-ablational enhancement (BPE), residual tumor, ablated tumor, adjacent liver parenchyma, and mean SUV of normal liver were measured, respectively. The ratios of SUVmax for these targets to mean SUV of normal liver (TNR) were calculated and statistically compared.

RESULTS

The mean TNR of non-treated liver tumors in group 1 was significantly greater than that of adjacent liver parenchyma (8.68 ± 0.71 vs 1.89 ± 0.26, p < 0.001). In group 2, the mean TNR of BPE was significantly greater than that of adjacent liver parenchyma (2.85 ± 0.20 vs 1.86 ± 0.25, p < 0.001). In group 3, the mean TNR of residual tumor was significantly greater than that of BPE (8.64 ± 0.59 vs 2.78 ± 0.23, p < 0.001), which was significantly greater than that of completely ablated tumor (2.78 ± 0.23 vs 0.50 ± 0.06, p < 0.001).

CONCLUSION

¹⁸F-FDG PET/MRI may serve as a promising imaging tool for early detection of viable residual tumors due to incomplete tumor ablation.

Insufficient ablation promotes the metastasis of residual non-small cell lung cancer (NSCLC) cells via upregulating carboxypeptidase A4

BACKGROUND

Thermal ablation is a potentially curative therapy for early-stage non-small cell lung cancer (NSCLC). Early recurrence after thermal ablation necessitates our attention.

METHODS

The invasion and migration abilities of NSCLC after sublethal heat stimulus were observed in vitro and in vivo. Sublethal thermal stimulus molecular changes were identified by RNA sequencing. A xenograft model of NSCLC with insufficient ablation was established to explore the epithelial-to-mesenchymal transition (EMT) and metastasis-related phenotypes alteration of residual tumors.

RESULTS

In vitro, the invasion and migration abilities of NSCLC cells were enhanced 72 h after 44 °C and 46 °C thermal stimulus. Epithelial-mesenchymal transition (EMT) phenotypes were also upregulated under these conditions. RNA sequencing revealed that the expression of carboxypeptidase A4 (CPA4) was significantly upregulated after thermal stimulus. Significant upregulation of CPA4 and EMT phenotypes was also found in the xenograft model of insufficient NSCLC ablation. The EMT process and invasion and migration abilities can be reversed by silencing CPA4.

CONCLUSIONS

This study demonstrates that sublethal heat stimulus caused by insufficient ablation can promote EMT and enhance the metastatic capacity of NSCLC. CPA4 plays an important role in these biological processes. Inhibition of CPA4 might be of great significance for improving early-stage NSCLC survival after ablation.

Incomplete thermal ablation-induced up-regulation of transcription factor nuclear receptor subfamily 2, group F, member 6 (NR2F6) contributes to the rapid progression of residual liver tumor in hepatoblastoma

Hepatoblastoma is a kind of extreme malignancy frequently diagnosed in children. Although surgical resection is considered as the first-line treatment for hepatoblastoma, a relatively large population of patients have lost the preferred opportunity for surgery. Administration of locoregional ablation enables local tumor control but with the deficiency of insufficient ablation, residual tumor, and rapid progression. In this study, we integrated 219 hepatoblastoma and 121 non-cancer liver tissues to evaluate the expression of NR2F6, from which a higher NR2F6 level was found in hepatoblastoma compared with non-cancer livers with a standard mean difference (SMD) of 1.04 (95% CI: 0.79, 1.29). The overexpression of NR2F6 also appeared to be an efficient indicator in distinguishing hepatoblastoma tissues from non-cancer liver tissues from the indication of a summarized AUC of 0.90, with a pooled sensitivity of 0.76 and a pooled specificity of 0.89. Interestingly, nude mouse xenografts provided direct evidence that overexpressed NR2F6 was also detected in residual tumor compared to untreated hepatoblastoma. Chromatin immunoprecipitation-binding data in HepG2 cells and transcriptome analysis of HepG2 xenografts were combined to identify target genes regulated by NR2F6. We finally selected 150 novel target genes of NR2F6 in residual tumor of incomplete ablation, and these genes appeared to be associated with the biological regulation of lipid metabolism-related pathway. Accordingly, targeting NR2F6 holds a therapeutic promise in treating residual recurrent hepatoblastoma after incomplete ablation.

Evaluation of Microwave Ablation in 4T1 Breast Tumor by a Novel VEFGR2 Targeted Ultrasound Contrast Agents

Objectives

A novel ultrasound contrast agent (UCA) VEGFR2-targeting iron-doped silica (SiO₂) hollow nanoparticles (VEGFR2-PEG-HSNs-Fe NPs) was prepared and applied in microwave ablation for breast cancer to investigate its value in the evaluation of effectiveness after tumor ablation.

Methods

VEGFR2-PEG-HSNs-Fe NPs were prepared by using nano-SiO₂, which was regarded as a substrate and etched by ferrous acetate, and then modified with anti-VEGFR2 antibody. Laser confocal microscope and flow cytometry were used to observe its main physicochemical properties, and biological safety was also investigated. After the xenograft tumor was treated with microwave ablation, the extent of perfusion defect was evaluated by ultrasound by injecting VEGFR2-PEG-HSNs-Fe NPs.

Results

The average particle size of VEGFR2-PEG-HSNs-Fe was 276.64 ± 30.31 nm, and the surface potential was −13.46 ± 2.83 mV. In vitro, the intensity of ultrasound signal increased with UCA concentration. Good biosafety was performed in in vivo and in vitro experiments. The enhanced ultrasound signal was detected in tumors after injection of VEGFR2-PEG-HSNs-Fe NPs, covering the whole tumor. The lesions, which were incompletely ablated, presented as contrast agent perfusion at the periphery of the tumor, and contrast enhanced ultrasound (CEUS) was performed again after complementary ablation. It was confirmed that all the lesions were completely ablated.

Conclusion

Nano-targeted UCAs VEGFR2-PEG-HSNs-Fe NPs had good biosafety and ability of specific imaging, which might be used as a contrast agent in CEUS to evaluate the efficacy of tumor ablation.

Radiofrequency ablation triggers the migration of hepatocellular carcinoma cells by suppressing miR-148a-5p

Increasing evidences suggest that insufficient radiofrequency ablation (IRFA) can paradoxically promote tumor invasion and metastatic processes, whereas the effects of moderate hyperthermia on cancer progression are not well illustrated. Our study found that IRFA can increase the in vitro migration, invasion, and epithelial-mesenchymal transition (EMT) of hepatocellular carcinoma (HCC) cells via induction of Snail, a master regulator of EMT events. Among measured miRNAs, IRFA can decrease the expression of miR-148a-5p in HCC cells. Whereas overexpression of miR-148a-5p can reverse IRFA-induced migration of HCC cells and upregulation of Snail, mechanistically overexpression of miR-148a-5p can directly target and decrease the expression of protein kinase ATM (ataxia telangiectasia mutated), which can increase protein stability of Snail. Collectively, our data suggest that IRFA can regulate the miR-148a-5p/ATM/Snail axis to trigger migration of HCC cells.

Hyperthermia by near infrared radiation induced immune cells activation and infiltration in breast tumor

Breast cancer is the most common cancer that causes death in women. Conventional therapies, including surgery and chemotherapy, have different therapeutic effects and are commonly associated with risks and side effects. Near infrared radiation is a technique with few side effects that is used for local hyperthermia, typically as an adjuvant to other cancer therapies. The understanding of the use of near NIR as a monotherapy, and its effects on the immune cells activation and infiltration, are limited. In this study, we investigate the effects of HT treatment using NIR on tumor regression and on the immune cells and molecules in breast tumors. Results from this study demonstrated that local HT by NIR at 43 °C reduced tumor progression and significantly increased the median survival of tumor-bearing mice. Immunohistochemical analysis revealed a significant reduction in cells proliferation in treated tumor, which was accompanied by an abundance of heat shock protein 70 (Hsp70). Increased numbers of activated dendritic cells were observed in the draining lymph nodes of the mice, along with infiltration of T cells, NK cells and B cells into the tumor. In contrast, tumor-infiltrated regulatory T cells were largely diminished from the tumor. In addition, higher IFN-γ and IL-2 secretion was observed in tumor of treated mice. Overall, results from this present study extends the understanding of using local HT by NIR to stimulate a favourable immune response against breast cancer.

Anlotinib enhances the antitumor activity of radiofrequency ablation on lung squamous cell carcinoma

Anlotinib is a novel molecular targeted drug that has been approved for the treatment of lung adenocarcinoma. Currently these agents are rarely used in the treatment of lung squamous cell carcinoma (LSCC). Bronchoscope-guided radiofrequency ablation (RFA) is a new strategy proposed for the treatment of LSCC that is able to alleviate the obstruction of the respiratory tract caused by LSCC by direct destruction of the tumor tissues. The presence work aims to reveal whether Anlotinib could enhance the antitumor activity of RFA on LSCC cells. The results from real-time PCR (qPCR) confirmed overexpression of targets of anlotinib activity, including receptor tyrosine kinase or the MPAK/PI3K-AKT pathway kinases, in LSCC tissues. Treatment with anlotinib inhibited the survival, in vitro invasion, and migration of LSCC cells. Moreover, the antitumor effects of RFA were investigated using a rodent model of LSCC. The combination of RFA and anlotinib treatment enhanced the antitumor effect of RFA treatment. We propose a combinative strategy of RFA and anlotinib as a novel approach for successful management of LSCC.

Flotillin membrane domains in cancer

Flotillins 1 and 2 are two ubiquitous, highly conserved homologous proteins that assemble to form heterotetramers at the cytoplasmic face of the plasma membrane in cholesterol- and sphingolipid-enriched domains. Flotillin heterotetramers can assemble into large oligomers to form molecular scaffolds that regulate the clustering of at the plasma membrane and activity of several receptors. Moreover, flotillins are upregulated in many invasive carcinomas and also in sarcoma, and this is associated with poor prognosis and metastasis formation. When upregulated, flotillins promote plasma membrane invagination and induce an endocytic pathway that allows the targeting of cargo proteins in the late endosomal compartment in which flotillins accumulate. These late endosomes are not degradative, and participate in the recycling and secretion of protein cargos. The cargos of this Upregulated Flotillin–Induced Trafficking (UFIT) pathway include molecules involved in signaling, adhesion, and extracellular matrix remodeling, thus favoring the acquisition of an invasive cellular behavior leading to metastasis formation. Thus, flotillin presence from the plasma membrane to the late endosomal compartment influences the activity, and even modifies the trafficking and fate of key protein cargos, favoring the development of diseases, for instance tumors. This review summarizes the current knowledge on flotillins and their role in cancer development focusing on their function in cellular membrane remodeling and vesicular trafficking regulation.

c-Met/MAPK pathway promotes the malignant progression of residual hepatocellular carcinoma cells after insufficient radiofrequency ablation

Radiofrequency ablation (RFA) is popularly used in the treatment of hepatocellular carcinoma (HCC). However, the accelerated malignant progression of residual HCC cells after RFA is the main obstacle for the application of this technology in HCC treatment. In the present study, HepG2 cells, an established human HCC cell line, experienced repeatedly with heat treatment, survived cells, HepG2-H cells, were used to simulate residual HCC cells after RFA. The abilities of proliferation, colony formation, and migration were compared between HepG2 and HepG2-H cells. Then, RNA sequencing was used to explore the difference in genes expression between two groups of cells. Subsequently, the level of c-Met, one of membranous receptors of MAPK signal pathway, was measured by RT-qPCR and western blot; the effect of c-Met inhibition on the malignant progression of HepG2-H cells was evaluated. The results showed that HepG2-H cells exhibited higher abilities in the proliferation, colony formation, and migration than that of HepG2 cells. Moreover, differentially expressed genes between two groups of cells were prominently enriched in MAPK signal pathway. The level of c-Met in HepG2-H cells was significantly higher than that in HepG2 cells, and the inhibition in the activity of c-Met could repress the malignant behaviors of HepG2-H cells. These results indicated that the accelerated malignant progression of residual HCC cells after RFA can be partly attributed to the overexpression of c-Met and the activation of MAPK signal pathway. Therefore, we proposed that RFA followed by c-Met inhibitor intake maybe is a better treatment protocol for HCC.

Specific Inhibitor of Matrix Metalloproteinase Decreases Tumor Invasiveness After Radiofrequency Ablation in Liver Tumor Animal Model

Objective

To determine whether the specific inhibitor of matrix metalloproteinase (MMP)-batimastat (BB-94)-could decrease the progression of liver tumor after radiofrequency ablation (RFA) and achieve better therapeutic efficacy in an animal model.

Methods

In vitro experiments, the proliferation of H22 liver tumor cells was detected by CCK 8 assay and cell migration was detected by Transwell method. In vivo experiments, H22 murine liver tumors were used. First, 32 mice with one tumor were randomized into four groups (n = 8 each group): control (PBS only), RFA alone (65°C, 5 min), BB-94 (30 mg/kg), RFA+BB-94. The growth rate of the residual tumor and the end point survival were calculated and the pathologic changes were evaluated. Secondly, a total of 48 tumors in 24 animals (paired tumors) were randomized into three groups (n = 8 each group): control, RFA alone, RFA+BB-94. Each mouse was implanted with two tumors subcutaneously, one tumor was treated by RFA and the other was evaluated for distant metastasis after applying BB-94.

Results

In vitro, the proliferation assay demonstrated higher proliferation ability after heat treatment (0.82 ± 0.07 vs 1.27 ± 0.08, P = 0.008), and it could be inhibited by BB-94 (1.27 ± 0.08 vs 0.67 ± 0.06, P = 0.001). In the cell migration assay, the H22 cells demonstrated enhanced tumor invasiveness in the heat group than the control group (33.7 ± 2.1 vs 19.7 ± 4.9, P = 0.011). And it could be significantly suppressed after BB-94 incubation (33.7 ± 2.1 vs 23.0 ± 4.6, P = 0.009). With one tumor animal, the growth rate of the residual tumor in the BB-94+RFA group was slower than that in the RFA alone group (P = 0.003). And combination of BB-94 could significantly prolong the survival of the mice (40.3 ± 1.4d vs 47.1 ± 1.3d, P = 0.002). The expression of CD31 and VEGF at the coagulation margin were decreased after combined with BB-94. With two tumors animal, the growth of metastasis tumor in the BB-94+RFA group was slower than that in the RFA group (P < 0.001).

Conclusion

BB-94 combined with RFA reduced the invasiveness of the liver tumor and improved the end-point survival. Our data suggested that targeting the MMP process with the specific inhibition could help to increase overall ablation efficacy.

Ten-Year Outcomes of Percutaneous Radiofrequency Ablation for Colorectal Cancer Liver Metastases in Perivascular vs. Non-Perivascular Locations: A Propensity-Score Matched Study

Purpose

To compare long-term outcomes of percutaneous radiofrequency ablation for colorectal liver metastases in perivascular versus non-perivascular locations.

Methods

This retrospective study included 388 consecutive patients with colorectal liver metastases (246 men, 142 women; age range 27–86 years) who underwent percutaneous radiofrequency ablation between January 2006 and December 2018. Propensity-score matching was performed for groups with perivascular and non-perivascular colorectal liver metastases. Rates of accumulative local tumor progression, overall survival, intra/extrahepatic recurrence, and complications were compared between the two groups.

Results

We successfully matched 104 patients each in the perivascular and non-perivascular groups (mean age: 60.1 ± 11.5 and 60.1 ± 11.3 years, respectively). Cumulative local tumor progression rates at 6 months, 1 years, 3 years, and 5 years, respectively, were 8.8%,14.8%, 18.9%, and 18.9% in the perivascular group and 8.8%, 13.1%, 15.5%, and 15.5% in the non-perivascular group. The 1-, 3-, 5-, and 10-year overall survival rates, respectively, were 91.3%, 45.6%, 23.9%, and 18.7% in the perivascular group and 88.0%, 47.2%, 27.2%, and 22.6% in the non-perivascular group. No significant between-group differences were detected in cumulative local tumor progression (p=0.567, hazard ratio: 1.224) or overall survival (p = 0.801, hazard ratio: 1.047). The major complication rate was 1.0% (1/104, p > 0.999) in both groups. Tumor size was the only independent prognostic factor for local tumor progression (hazard ratio: 2.314; p = 0.002). On multivariate analysis for overall colorectal liver metastases, tumor diameter >3 cm, tumor location in the right colon, multiple tumors, and extrahepatic metastases before radiofrequency ablation (hazard ratios: 2.046, 1.920, 1.706, and 1.892, respectively; all p < 0.001) and intrahepatic recurrence (hazard ratio: 1.564; p = 0.002) were associated with poor overall survival.

Conclusion

Cumulative local tumor progression, overall survival, and major complications rates did not differ significantly between perivascular and non-perivascular colorectal liver metastases after percutaneous radiofrequency ablation. For perivascular colorectal liver metastases, percutaneous radiofrequency ablation is a safe and effective treatment option.

Ultrasound Molecular Imaging as a Potential Non-invasive Diagnosis to Detect the Margin of Hepatocarcinoma via CSF-1R Targeting

Though radiofrequency ablation (RFA) is considered to be an effective treatment for hepatocellular carcinoma (HCC), but more than 30% of patients may suffer insufficient RFA (IRFA), which can promote more aggressive of the residual tumor. One possible method to counter this is to accurately identify the margin of the HCC. Colony-stimulating factor 1 receptor (CSF-1R) has been found to be restrictively expressed by tumor associated macrophages (TAMs) and monocytes which more prefer to locate at the boundary of HCC. Using biotinylation method, we developed a CSF-1R-conjugated nanobubble CSF-1R (NB_CSF–1R) using a thin-film hydration method for margin detection of HCC. CSF-1R expression was higher in macrophages than in HCC cell lines. Furthermore, immunofluorescence showed that CSF-1R were largely located in the margin of xenograft tumor and IFRA models. In vitro, NB_CSF–1R was stable and provided a clear ultrasound image even after being stored for 6 months. In co-culture, NB_CSF–1R adhered to macrophages significantly better than HCC cells (p = 0.05). In in vivo contrast-enhanced ultrasound imaging, the washout half-time of the NB_CSF–1R was significantly greater than that of NB_CTRL and Sonovue^® (p = 0.05). The signal intensity of the tumor periphery was higher than the tumor center or non-tumor region after NB_CSF–1R injection. Taken together, NB_CSF–1R may potentially be used as a non-invasive diagnostic modality in the margin detection of HCC, thereby improving the efficiency of RFA. This platform may also serve as a complement method to detect residual HCC after RFA; and may also be used for targeted delivery of therapeutic drugs or genes.

Iodine-125 Brachytherapy Can Prolong Progression-Free Survival of Patients with Locoregional Recurrence and/or Residual Hepatocellular Carcinoma After Radiofrequency Ablation

Background: Radiofrequency ablation (RFA) for the treatment of hepatocellular carcinoma (HCC) is limited by locoregional recurrence and/or residual tumors caused by incomplete ablation. Iodine-125 brachytherapy can achieve a high local control rate in solid carcinoma, but few studies have assessed the efficacy of this treatment for locoregional recurrence and/or residual HCC after RFA. Objective: To investigate the effectiveness and safety of iodine-125 brachytherapy for treating locoregional recurrence and/or residual HCC in patients treated with RFA. Methods: Eligible study patients were those with locoregional recurrence and/or residual HCC on abdominal imaging performed 1 month after RFA at this institution between February 2009 and September 2014 retrospectively. Patients were divided into either the control group (no treatment until the tumor progressed) or the treatment group (underwent iodine-125 brachytherapy). Progression-free survival (PFS), overall survival (OS), and complications of iodine-125 brachytherapy were evaluated. Results: A total of 42 patients were included in the final analysis, including 29 in the control group and 13 in the treatment group. A total of 457 iodine-125 particles were used (mean 32.8 ± 21.3 mCi per case). The median follow-up time was 25 months. Median PFS was 9 months in the control group and 18 months in the treatment group (p = 0.026). The median OS was 28 months in the control group and 33 months in the treatment group (p = 0.441). There were no major complications observed in patients treated with iodine-125 brachytherapy. Conclusion: Iodine-125 brachytherapy can prolong PFS in patients with locoregional recurrence and/or residual HCC after RFA.

Radiofrequency ablation with four electrodes as a building block for matrix radiofrequency ablation: Ex vivo liver experiments and finite element method modelling. Influence of electric and activation mode on coagulation size and geometry

PURPOSE

Radiofrequency ablation (RFA) is increasingly being used to treat unresectable liver tumors. Complete ablation of the tumor and a safety margin is necessary to prevent local recurrence. With current electrodes, size and shape of the ablation zone are highly variable leading to unsatisfactory local recurrence rates, especially for tumors >3 cm. In order to improve predictability, we recently developed a system with four simple electrodes with complete ablation in between the electrodes. This rather small but reliable ablation zone is considered as a building block for matrix radiofrequency ablation (MRFA). In the current study we explored the influence of the electric mode (monopolar or bipolar) and the activation mode (consecutive, simultaneous or switching) on the size and geometry of the ablation zone.

MATERIALS AND METHODS

The four electrode system was applied in ex vivo bovine liver. The electric and the activation mode were changed one by one, using constant power of 50 W in all experiments. Size and geometry of the ablation zone were measured. Finite element method (FEM) modelling of the experiment was performed.

RESULTS

In ex vivo liver, a complete and predictable coagulation zone of a 3 × 2 × 2 cm block was obtained most efficiently in the bipolar simultaneous mode due to the combination of the higher heating efficacy of the bipolar mode and the lower impedance by the simultaneous activation of four electrodes, as supported by the FEM simulation.

CONCLUSIONS

In ex vivo liver, the four electrode system used in a bipolar simultaneous mode offers the best perspectives as building block for MRFA. These results should be confirmed by in vivo experiments.

Comparison of open liver resection and RFA for the treatment of solitary 3-5-cmhepatocellular carcinoma: a retrospective study

BACKGROUND

The goal of this study was to compare the postoperative results of liver resection and radiofrequency ablation (RFA) for the treatment of small hepatocellular carcinoma (HCC) (3-5 cm).

PATIENTS AND METHODS

We retrospectively collected 122 cases of small solitary HCC treated at our center from Jan 2011 to Dec 2015, with diameters in the range of 3-5 cm. According to the treatment program received at our center, the patients were divided into liver resection (72 patients) and RFA (50 patients) groups.

RESULT

In comparison with the RFA group, the resection group had a longer operative time, greater intraoperative blood loss (P < 0.01), more hepatic inflow occlusion, and a longer postoperative hospital stay (P < 0.01). The 1-, 3-, and 5-year expected overall survival rates and tumor-free survival rates were comparable between the two groups. Cox regression analysis showed that neither resection nor RFA was a significant risk factor for overall or tumor-free survival in HCC.

CONCLUSIONS

For solitary HCC of 3-5 cm in diameter, RFA can achieve better in-hospital clinical results and similar long-term outcomes than resection and can be considered for wide application, especially for central-location cases.