Insufficient radiofrequency ablation promotes proliferation of residual hepatocellular carcinoma via autophagy. Cancer Lett. 2018;421:73-81. [PMID: 29458142 DOI: 10.1016/j.canlet.2018.02.024]

Nomogram to Predict Tumor Remnant of Small Hepatocellular Carcinoma after Microwave Ablation

RATIONALE AND OBJECTIVES

This investigation sought to create a nomogram to predict the ablation effect after microwave ablation in patients with hepatocellular carcinoma, which can guide the selection of microwave ablation for small hepatocellular carcinomas.

METHODS

In this two-center retrospective study, 233 patients with hepatocellular carcinoma treated with microwave ablation (MWA) between January 2016 and December 2023 were enrolled and analyzed for their clinical baseline data, laboratory parameters, and MR imaging characteristics. Logistic regression analysis was used to screen the features, and clinical and imaging feature models were developed separately. Finally, a nomogram was established. All models were evaluated using the area under the curve (AUC), accuracy, sensitivity, specificity, and decision curve analysis (DCA).

RESULTS

Two models and a nomogram were developed to predict ablation outcomes after MWA based on a training set (n = 182, including complete ablation: 136, incomplete ablation: 46) and an external validation set (n = 51, complete ablation: 36, incomplete ablation: 15). The clinical models and nomogram performed well in the external validation cohort. The AUC of the nomogram was 0.966 (95% CI: 0.944- 0.989), with a sensitivity of 0.935, a specificity of 0.882, and an accuracy of 0.896.

CONCLUSIONS

Combining clinical data and imaging features, a nomogram was constructed that could effectively predict the postoperative ablation outcome in hepatocellular carcinoma patients undergoing MWA, which could help clinicians provide treatment options for hepatocellular carcinoma patients.

Co-inhibition of RAGE and TLR4 sensitizes pancreatic cancer to irreversible electroporation in mice by disrupting autophagy

Irreversible electroporation (IRE) is a local ablative treatment for patients with pancreatic cancer. During the IRE procedure, high-intensity electric pulses are released intratumorally to disrupt plasma membranes and induce cell death. Since the intensity of the pulsed electric field (PEF) can be decreased by the tumor microenvironment, some cancer cells are subjected to a sublethal PEF and may survive to cause tumor recurrence later. Autophagy activation induced by anticancer therapies is known to promote treatment resistance. In this study, we investigated whether autophagy is activated in residual cancer cells after IRE and assessed the roles it plays during tumor recurrence. Subcutaneous KPC-A548 or Panc02 murine pancreatic cancer cell line xenograft mouse models were established; once the tumors reached 7 mm in one dimension, the tumor-bearing mice were subjected to IRE. For in vitro sublethal PEF treatment, the pancreatic cancer cell suspension was in direct contact with the electrodes and pulsed at room temperature. We showed that autophagy was activated in surviving residual cells, as evidenced by increased expression of LC3 and p62. Suppression of autophagy with hydroxychloroquine (60 mg/kg, daily intraperitoneal injection) markedly increased the efficacy of IRE. We demonstrated that autophagy activation can be attributed to increased expression of high-mobility group box 1 (HMGB1); co-inhibition of two HMGB1 receptors, receptor for advanced glycosylation end products (RAGE) and Toll-like receptor 4 (TLR4), suppressed autophagy activation by upregulating the PI3K/AKT/p70 ribosomal S6 protein kinase (p70S6K) axis and sensitized pancreatic cancer cells to PEF. We prepared a polymeric micelle formulation (M-R/T) encapsulating inhibitors of both RAGE and TLR4. The combination of IRE and M-R/T (equivalent to RAGE inhibitor at 10.4 mg/kg and TLR4 inhibitor at 5.7 mg/kg, intravenous or intraperitoneal injection every other day) significantly promoted tumor apoptosis, suppressed cell cycle progression, and prolonged animal survival in pancreatic tumor models. This study suggests that disruption of HMGB1-mediated autophagy with nanomedicine is a promising strategy to enhance the response of pancreatic cancer to IRE.

Autophagy-based therapy for hepatocellular carcinoma: from standard treatments to combination therapy, oncolytic virotherapy, and targeted nanomedicines

Human hepatocellular carcinoma (HCC) has been identified as a significant cause of mortality worldwide. In recent years, extensive research has been conducted to understand the underlying mechanisms of autophagy in the pathogenesis of the disease, with the aim of developing novel therapeutic agents. Targeting autophagy with conventional therapies in invasive HCC has opened up new opportunities for treatment. However, the emergence of resistance and the immunosuppressive tumor environment highlight the need for combination therapy or specific targeting, as well as an efficient drug delivery system to ensure targeted tumor areas receive sufficient doses without affecting normal cells or tissues. In this review, we discuss the findings of several studies that have explored autophagy as a potential therapeutic approach in HCC. We also outline the potential and limitations of standard therapies for autophagy modulation in HCC treatment. Additionally, we discuss how different combination therapies, nano-targeted strategies, and oncolytic virotherapy could enhance autophagy-based HCC treatment in future research.

Simultaneous inhibition of heat shock proteins and autophagy enhances radiofrequency ablation of hepatocellular carcinoma

Radiofrequency ablation (RFA) is a commonly used minimally invasive treatment for hepatocellular carcinoma (HCC). However, incomplete radiofrequency ablation (iRFA) promotes tumor progression and metastasis. There is an urgent need to develop innovative strategies to enhance the efficacy of iRFA. The upregulation of heat shock proteins (HSPs) and activation of protective autophagy in tumor cells upon exposure to sublethal heat enhance the thermotolerance, thereby promoting tumor cell survival. Here, 3-methyladenine (3-MA) and lonidamine (LND) co-encapsulated liposomes (Lip@LND/3-MA) are designed to enhance the efficacy of iRFA by simultaneous inhibition of glycolysis and autophagy. On one hand, LND inhibits hexokinase, a key enzyme in glycolysis, and thus reduces ATP production and consequently suppresses the expression of HSPs. On the other hand, 3-MA, as an autophagy inhibitor, can inhibit protective autophagy after iRFA. Lip@LND/3-MA is confirmed to suppress the expression of HSPs and reduce the autophagy level during RFA. Therefore, the thermotolerance of tumor cells is significantly weakened, leading to remarkably enhanced therapeutic efficacy of iRFA. It is believed that simultaneous inhibition of HSPs and autophagy is a promising therapeutic strategy in clinical practice of RFA.

Radiofrequency ablation: mechanisms and clinical applications

Radiofrequency ablation (RFA), a form of thermal ablation, employs localized heat to induce protein denaturation in tissue cells, resulting in cell death. It has emerged as a viable treatment option for patients who are ineligible for surgery in various diseases, particularly liver cancer and other tumor-related conditions. In addition to directly eliminating tumor cells, RFA also induces alterations in the infiltrating cells within the tumor microenvironment (TME), which can significantly impact treatment outcomes. Moreover, incomplete RFA (iRFA) may lead to tumor recurrence and metastasis. The current challenge is to enhance the efficacy of RFA by elucidating its underlying mechanisms. This review discusses the clinical applications of RFA in treating various diseases and the mechanisms that contribute to the survival and invasion of tumor cells following iRFA, including the roles of heat shock proteins, hypoxia, and autophagy. Additionally, we analyze‌ the changes occurring in infiltrating cells within the TME after iRFA. Finally, we provide a comprehensive summary of clinical trials involving RFA in conjunction with other treatment modalities in the field of cancer therapy, aiming to offer novel insights and references for improving the effectiveness of RFA.

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.

Transarterial chemoembolization combined with radiofrequency ablation for medium and large hepatocellular carcinoma: insufficient ablation is associated with intrahepatic distant metastasis and extrahepatic metastasis

Purpose

To compare the prognosis of complete and insufficient ablation of transarterial chemoembolization (TACE) combined with radiofrequency ablation (RFA) in treating medium and large hepatocellular carcinoma (HCC) and to explore the differences in recurrence patterns between the two groups.

Patients and methods

Patients´ medical records and imaging data of patients with confirmed HCC from January 2014 to January 2022 were collected. These patients were divided into 2 groups: complete ablation (n=172) and insufficient ablation (n=171). Overall survival (OS) and progression-free survival (PFS) were estimated by the Kaplan-Meier curve and the log-rank test was used to compared. Fisher's exact test was used to compare recurrence patterns between the two groups.

Results

The median OS time was 72.8 months (95%CI:69.5-76.1) and 62.0 months (95%CI: 55.3-68.7) in the complete and insufficient ablation groups, respectively. The median PFS time in the complete ablation group was 67.8 months (95% CI: 65.2-70.4) and 38.6 months (95%CI: 29.8-47.4) in the insufficient ablation group. The OS and PFS rates of the complete ablation group were significantly better than those of the insufficient ablation group (P<0.001). In the complete ablation group, 25(41%) patients experienced local tumor progression(LTP), 36(59%) experienced intrahepatic distant progression(IDP), and 0(0%) experienced extrahepatic progression (EP). In the insufficient ablation group, 51 (32.1%) patients experienced LTP, 96 (60.4%) experienced IDP, and 12 (7.5%) experienced EP. The progression patterns of the two groups were statistically significant (P=0.039).

Conclusion

Insufficient ablation indicates a poor survival outcome of TACE combined with RFA for medium and large HCC and can promote intrahepatic distant and extrahepatic metastasis.

Size-Tunable Nanoregulator-Based Radiofrequency Ablation Suppresses MDSCs and Their Compensatory Immune Evasion in Hepatocellular Carcinoma

Radiofrequency ablation (RFA) is a widely used therapy for hepatocellular carcinoma (HCC). However, in cases of insufficient RFA (iRFA), nonlethal temperatures in the transition zone increase the risk of postoperative relapse. The pathological analysis of HCC tissues shows that iRFA-induced upregulation of myeloid-derived suppressor cells (MDSCs) in residual tumors is critical for postoperative recurrence. Furthermore, this study demonstrates, for the first time, that combining MDSCs suppression strategy during iRFA can unexpectedly lead to a compensatory increase in PD-L1 expression on the residual MDSCs, attributed to relapse due to immune evasion. To address this issue, a novel size-tunable hybrid nano-microliposome is designed to co-deliver MDSCs inhibitors (IPI549) and αPDL1 antibodies (LPIP) for multipathway activation of immune responses. The LPIP is triggered to release immune regulators by the mild heat in the transition zone of iRFA, selectively inhibiting MDSCs and blocking the compensatory upregulation of PD-L1 on surviving MDSCs. The combined strategy of LPIP + iRFA effectively ablates the primary tumor by activating immune responses in the transition zone while suppressing the compensatory immune evasion of surviving MDSCs. This approach avoids the relapse of the residual tumor in a post-iRFA incomplete ablation model and appears to be a promising strategy in RFA for the eradication of HCC.

Mechanisms and therapeutic strategies to combat the recurrence and progression of hepatocellular carcinoma after thermal ablation

Thermal ablation (TA), including radiofrequency ablation (RFA) and microwave ablation (MWA), has become the main treatment for early-stage hepatocellular carcinoma (HCC) due to advantages such as safety and minimal invasiveness. However, HCC is prone to local recurrence, with more aggressive malignancies after TA closely related to TA-induced changes in epithelial-mesenchymal transition (EMT) and remodeling of the tumor microenvironment (TME). According to many studies, various components of the TME undergo complex changes after TA, such as the recruitment of innate and adaptive immune cells, the release of tumor-associated antigens (TAAs) and various cytokines, the formation of a hypoxic microenvironment, and tumor angiogenesis. Changes in the TME after TA can partly enhance the anti-tumor immune response; however, this response is weak to kill the tumor completely. Certain components of the TME can induce an immunosuppressive microenvironment through complex interactions, leading to tumor recurrence and progression. How the TME is remodeled after TA and the mechanism by which the TME promotes HCC recurrence and progression are unclear. Thus, in this review, we focused on these issues to highlight potentially effective strategies for reducing and preventing the recurrence and progression of HCC after TA.

Autophagy-amplifying nanoparticles evoke immunogenic cell death combined with anti-PD-1/PD-L1 for residual tumors immunotherapy after RFA

Incomplete radiofrequency ablation (IRFA) triggers mild protective autophagy in residual tumor cells and results in an immunosuppressive microenvironment. This accelerates the recurrence of residual tumors and causes resistance to anti-PD-1/PDL1 therapy, which bringing a great clinical challenge in residual tumors immunotherapy. Mild autophagy activation can promote cancer cell survival while further amplification of autophagy contributes to immunogenic cell death (ICD). To this regard, we constructed active targeting zeolitic imidazolate framework-8 (ZIF-8) nanoparticles (NPs) loaded with STF62247 or both STF62247 and BMS202, namely STF62247@ZIF-8/PEG-FA (SZP) or STF62247-BMS202@ZIF-8/PEG-FA (SBZP) NPs. We found that SZP NPs inhibited proliferation and stimulated apoptosis of residual tumor cells exposed to sublethal heat stress in an autophagy-dependent manner. Further results discovered that SZP NPs could amplify autophagy in residual tumor cells and evoke their ICD, which dramatically boosted the maturation of dendritic cells (DCs). Through vaccination experiments, we found for the first time that vaccination with heat + SZP treatment could efficiently suppress the growth of new tumors and establish long-term immunological memory. Furthermore, SBZP NPs could remarkably promote the ICD of residual tumor cells, obviously activate the anti-tumor immune microenvironment, and significantly inhibit the growth of residual tumors. Thus, amplified autophagy coupled with anti-PD-1/PDL1 therapy is potentially a novel strategy for treating residual tumors after IRFA.

Synergistic effect of OK-432 in combination with an anti-PD-1 antibody for residual tumors after radiofrequency ablation of hepatocellular carcinoma

BACKGROUND AND AIMS

Radiofrequency ablation (RFA) often results in incomplete ablation for medium-to-large and irregular tumors. To solve this clinical problem, we proposed a new treatment strategy of OK-432 in combination with an anti-programmed cell death protein 1 (αPD-1) antibody for residual tumors after incomplete RFA (iRFA) of hepatocellular carcinoma (HCC).

APPROACH AND RESULTS

The effect of OK-432 on immature dendritic cells (iDCs) was evaluated in vitro. A CCK-8 kit and ELISPOT were used to assess the killing effect of OK-432-induced CD8+ T cells in combination with an αPD-1 antibody on Hepa1-6 cells. We found that OK-432 significantly increased the maturation level of DCs, and OK-432-induced CD8+ T cells in combination with αPD-1 antibody significantly enhanced the function of CD8+ T cells. In the in vivo experiment, HCC model mice were treated with (1) pseudo iRFA + phosphate-buffered saline (PBS); (2) iRFA + PBS; (3) iRFA + OK-432; (4) iRFA + αPD-1; or (5) iRFA + OK-432 + αPD-1. We found that the combined therapy of OK-432 with αPD-1 antibody significantly increased the infiltration and function of CD8+ T cells and significantly decreased the number of FoxP3+ regulatory T cells in residual tumors after iRFA of HCC. Moreover, the smallest tumor volumes and the longest survival were observed in the triple combination treatment (iRFA+OK-432 +αPD-1 antibody) group compared with the other four groups.

CONCLUSIONS

The combined therapy of OK-432 with αPD-1 antibody induced a strong antitumor immune response, which significantly inhibited the residual tumors after iRFA of HCC. This concept may provide a new treatment strategy to increase the curative efficacy of RFA for medium-to-large and irregular HCCs.

AVAILABILITY OF DATA AND MATERIAL

The data of this study are available from the corresponding author on reasonable request.

Incomplete radiofrequency ablation following transarterial chemoembolization accelerates the progression of large hepatocellular carcinoma

Purpose

To examine post-operative progression and risk impact of insufficient radiofrequency ablation (RFA) following transarterial chemoembolization (TACE) for the prognosis of large hepatocellular carcinoma (HCC).

Materials and Methods

From January 2014 to January 2021 were analyzed. A total of 343 patients with large HCC (diameter >5 cm) who received TACE combined with RFA were enrolled and were divided into two groups: complete ablation (CA, n = 172) and insufficient ablation (IA, n = 171). Overall survival (OS) and progression-free survival (PFS) were determined by the Kaplan-Meier curve and compared with the log-rank test. To find parameters influencing OS and PFS, clinicopathological variables underwent univariate and multivariate analysis.

Results

The cumulative 1-, 3-, and 5-year OS and PFS rates of the CA group were significantly higher than that of the IA group (P < 0.001). 25 (41%) patients in local tumor progression (LTP), 36 (59%) in intrahepatic distant recurrence (IDR), and 0 (0%) in extrahepatic distant recurrence (EDR) in the CA group. 51 (32.1%) patients in LTP, 96 (60.4%) patients in IDR, and 12 (7.5%) cases in EDR in the IA group. The recurrence patterns of the two groups were statistically significant difference (P = 0.039). In multivariate analysis, inadequate ablation and conjunction with TKIs were both significant risk factors for OS and PFS. Apart from these, older age and >7 cm of tumor size were indicators of poor OS and multiple tumors were indicators of poor PFS.

Conclusion

Insufficient ablation causes a poor survival outcome of TACE combined with RFA for large HCC, particularly, which can promote IDR.

Immunomodulatory effect of locoregional therapy in the tumor microenvironment

Cancer immunotherapy appears to be a promising treatment option; however, only a subset of patients with cancer responds favorably to treatment. Locoregional therapy initiates a local antitumor immune response by disrupting immunosuppressive components, releasing immunostimulatory damage-associated molecular patterns, recruiting immune effectors, and remodeling the tumor microenvironment. Many studies have shown that locoregional therapy can produce specific antitumor immunity alone; nevertheless, the effect is relatively weak and transient. Furthermore, increasing research efforts have explored the potential synergy between locoregional therapy and immunotherapy to enhance the long-term systemic antitumor immune effect and improve survival. Therefore, further research is needed into the immunomodulatory effects of locoregional therapy and immunotherapy to augment antitumor effects. This review article summarizes the key components of the tumor microenvironment, discusses the immunomodulatory role of locoregional therapy in the tumor microenvironment, and emphasizes the therapeutic potential of locoregional therapy in combination with immune checkpoint inhibitors.

Eliminating METTL1-mediated accumulation of PMN-MDSCs prevents hepatocellular carcinoma recurrence after radiofrequency ablation

BACKGROUND AND AIMS

Radiofrequency ablation (RFA) is an important curative therapy in hepatocellular carcinoma (HCC), but recurrence rate remains as high as all the other HCC therapeutic modalities. Methyltransferase 1 (METTL1), an enzyme for m 7 G tRNA modification, was reported to promote HCC development. Here, we assessed the role of METTL1 in shaping the immunosuppressive tumor microenvironment after insufficient RFA (iRFA).

APPROACH AND RESULTS

By immunohistochemistry and multiplex immunofluorescence (mIF) staining, we showed that METTL1 expression was enhanced in post-RFA recurrent HCC, accompanied by increased CD11b + CD15 + polymorphonuclear-myeloid-derived suppressor cells (PMN-MDSCs) and decreased CD8 + T cells. Mechanistically, heat-mediated METTL1 upregulation enhanced TGF-β2 translation to form the immunosuppressive environment by induction of myeloid-derived suppressor cell. Liver-specific overexpression or knockdown of Mettl1 significantly affected the accumulation of PMN-MDSCs and subsequently affected CD8 + T cell infiltration. Complete RFA successfully eliminated the tumor, whereas iRFA-treated mice exhibited enhanced tumor growth and metastasis with increased PMN-MDSC accumulation and decreased CD8 + T cells compared to sham surgery. Interrupting METTL1-TGF-β2-PMN-MDSC axis by anti-Ly6G antibody, or knockdown of hepatoma-intrinsic Mettl1 or Tgfb2 , or TGF-β signaling blockade significantly mitigated tumor progression induced by iRFA and restored CD8 + T cell population.

CONCLUSIONS

Our study sheds light on the pivotal role of METTL1 in modulating an immunosuppressive microenvironment and demonstrated that interrupting METTL1-TGF-β2-PMN-MDSC axis could be a therapeutic strategy to restore antitumor immunity and prevent HCC recurrence after RFA treatment, meriting further clinical studies.

Mitochondrial ROS driven by NOX4 upregulation promotes hepatocellular carcinoma cell survival after incomplete radiofrequency ablation by inducing of mitophagy via Nrf2/PINK1

BACKGROUND

The recurrence of hepatocellular carcinoma (HCC) after radiofrequency ablation (RFA) remains a major clinical problem. Cells that survive the sublethal heat stress that is induced by incomplete RFA are the main source of HCC relapse. Heat stress has long been reported to increase intracellular reactive oxygen species (ROS) generation. Although ROS can induce apoptosis, a pro-survival effect of ROS has also been demonstrated. However, the role of ROS in HCC cells exposed to sublethal heat stress remains unclear.

METHODS

HepG2 and HuH7 cells were used for this experiment. Insufficient RFA was performed in cells and in a xenograft model. ROS and antioxidant levels were measured. Apoptosis was analyed by Annexin-V/PI staining and flow cytometry. Protein expression was measured using western blotting. Colocalization of lysosomes and mitochondria was analyzed to assess mitophagy. Corresponding activators or inhibitors were applied to verify the function of specific objectives.

RESULTS

Here,we showed that sublethal heat stress induced a ROS burst, which caused acute oxidative stress. This ROS burst was generated by mitochondria, and it was initiated by upregulated NOX4 expression in the mitochondria. N-acetylcysteine (NAC) decreased HCC cell survival under sublethal heat stress conditions in vivo and in vitro. NOX4 triggers the production of mitochondrial ROS (mtROS), and NOX4 inhibitors or siNOX4 also decreased HCC cell survival under sublethal heat stress conditions in vitro. Increased mtROS trigger PINK1-dependent mitophagy to eliminate the mitochondria that are damaged by sublethal heat stress and to protect cells from apoptosis. Nrf2 expression was elevated in response to this ROS burst and mediated the ROS burst-induced increase in PINK1 expression after sublethal heat stress.

CONCLUSION

These data confirmed that the ROS burst that occurs after iRFA exerted a pro-survival effect. NOX4 increased the generation of ROS by mitochondria. This short-term ROS burst induced PINK1-dependent mitophagy to eliminate damaged mitochondria by increasing Nrf2 expression.

HMGB1 released from dead tumor cells after insufficient radiofrequency ablation promotes progression of HCC residual tumor via ERK1/2 pathway

BACKGROUND

Radiofrequency ablation (RFA) is a first-line treatment for early-stage hepatocellular carcinoma (HCC). However, the recurrence after RFA remains an urgent challenge. Current studies have shown that residual tumor after RFA is an important cause of recurrence.

OBJECTIVE

We hypothesized that the products of dead tumor cells after RFA have direct effects on the development of residual tumors. Further, we investigated the underlying mechanisms.

METHODS

The proliferation and invasion ability of HepG2 and Huh7 cells were assessed using CCK-8, colony formation, EdU, transwell invasion and migration assay. Immunofluorescence and western blotting were used to show HMGB1 released from dead tumor cells. The levels of MMP2, MMP9, CyclinE1 and pERK1/2 were determined using western blotting. Finally, in vivo validation was performed in BALB/c nude mice xenograft tumor models.

RESULTS

The products of dead tumor cells after thermal treatment can promote the proliferation and invasion of residual HCC cells. Dead tumor cells could release high-mobility group box 1 (HMGB1) after thermal treatment. Similar to the products of dead tumor cells, the recombinant protein of HMGB1 can promote the proliferation and invasion of residual HCC cells. Moreover, HMGB1 could bind to receptor of advanced glycation end-products. Then, it activated the ERK1/2 pathway and significantly upregulated the expressions of MMP2, MMP9, and CyclinE1.

CONCLUSION

Our study reveals that HMGB1 released by dead tumor cells after thermal treatment can promote the proliferation and invasion of residual HCC cells. Hence, the HMGB1/RAGE/ERK1/2 pathway is a potential target for improving the prognosis of HCC after radiofrequency ablation.

Roles of hypoxia-inducible factor in hepatocellular carcinoma under local ablation therapies

Hepatocellular carcinoma (HCC) is one of the most common digestive malignancies. HCC It ranges as the fifth most common cause of cancer mortality worldwide. While The prognosis of metastatic or advanced HCC is still quite poor. Recently, locoregional treatment, especially local ablation therapies, plays an important role in the treatment of HCC. Radiofrequency ablation (RFA) and high-intensity focused ultrasound (HIFU) ablation are the most common-used methods effective and feasible for treating HCC. However, the molecular mechanisms underlying the actions of ablation in the treatments for HCC and the HCC recurrence after ablation still are poorly understood. Hypoxia-inducible factor (HIF), the key gene switch for adaptive responses to hypoxia, has been found to play an essential role in the rapid aggressive recurrence of HCC after ablation treatment. In this review, we summarized the current evidence of the roles of HIF in the treatment of HCC with ablation. Fifteen relevant studies were included and further analyzed. Among them, three clinical studies suggested that HIF-1α might serve as a crucial role in the RAF treatment of HCC or the local recurrence of HCC after RFA. The remainder included experimental studies demonstrated that HIF-1, 2α might target the different molecules (e.g., BNIP3, CA-IX, and arginase-1) and signaling cascades (e.g., VEGFA/EphA2 pathway), constituting a complex network that promoted HCC invasion and metastasis after ablation. Currently, the inhibitors of HIF have been developed, providing important proof of targeting HIF for the prevention of HCC recurrence after IRFA and HIFU ablation. Further confirmation by prospective clinical and in-depth experimental studies is still warranted to illustrate the effects of HIF in HCC recurrence followed ablation treatment in the future.

Heat treatment-induced autophagy promotes breast cancer cell invasion and metastasis via TGF-β2-mediated epithelial-mesenchymal transitions

Background

Insufficient thermal ablation can accelerate malignant behaviors and metastases in some solid tumors, and epithelial-mesenchymal transition (EMT) and autophagy are involved in tumor metastasis. It has been found that TGF-β2 which belongs to the family of transforming growth factors often associated with cancer cell invasiveness and EMT. However, whether the interactions between autophagy and TGF-β2 induce EMT in breast cancer (BC) cells following insufficient microwave ablation (MWA) remains unclear.

Methods

BC cells were treated with sublethal heat treatment to simulate insufficient MWA, and the effects of heat treatment on the BC cell phenotypes were explored. CCK-8, colony formation, flow cytometry, Transwell, and wound healing assays were performed to evaluate the influence of sublethal heat treatment on the proliferation, apoptosis, invasion, and migration of BC cells. Western blotting, real-time quantitative PCR, immunofluorescence, and transmission electron microscopy were carried out to determine the changes in markers associated with autophagy and EMT following sublethal heat treatment.

Results

Results showed that heat treatment promoted the proliferation of surviving BC cells, which was accompanied by autophagy induction. Heat treatment-induced autophagy up-regulated TGF-β2/Smad2 signaling and promoted EMT phenotype, thereby enhancing BC cells' migration and invasion abilities. An increase or decrease of TGF-β2 expression resulted in the potentiation and suppression of autophagy, as well as the enhancement and abatement of EMT. Autophagy inhibitors facilitated apoptosis and repressed proliferation of BC cells in vitro, and thwarted BC cell tumor growth and pulmonary metastasis in vivo.

Conclusion

Heat treatment-induced autophagy promoted invasion and metastasis via TGF-β2/Smad2-mediated EMTs. Suppressing autophagy may be a suitable strategy for overcoming the progression and metastasis of residual BC cells following insufficient MWA.

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.

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.

Intelligent Algorithm-Based Ultrasound Images in Evaluation of Therapeutic Effects of Radiofrequency Ablation for Liver Tumor and Analysis on Risk Factors of Postoperative Infection

This research aimed to explore the therapeutic effects of radiofrequency ablation (RFA) for liver tumors and to investigate the postoperative infection factors. Specifically, 80 patients with liver tumors undergoing ultrasound-guided FRA were selected as research subjects. They were diagnosed in the hospital. An intelligent fitting (IF) algorithm was compared with a genetic algorithm (GA) and applied to the RFA of the 80 patients. It was found that the running time of the IF algorithm was about 0.2 times than that of the GA, demonstrating better global searching capabilities. The mean diameter of single liver tumors was (3.45 ± 1.24) cm, and the complete ablation rate of tumors with diameters less than 3 cm was 87.88%, that of tumors with diameters of 3-5 cm was 72.92%, and that of tumors with a diameter of more than 5 cm was 63.33%. Posttreatment, the AST level decreased significantly and the ALB level increased significantly, and the difference was notable (P < 0.05P<); the TBIL level (36.8 ± 9.7 umol/L) was lower than prior treatment (17.9 ± 8.5 umol/L) and the ALT level (45.2 ± 6.8 g/L) was lower than prior treatment (19.6 ± 5.7 g/L), showing a notable difference (P < 0.05P<). The diameter, whether there was great vessel invasion, and TNM staging were associated with infection after RFA, and the difference was notable. The ultrasound images can effectively evaluate the therapeutic effects of RFA and the degree of inactivation of liver tumors. In addition, the tumor stage was an independent risk factor for postoperative infection.

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.

Comparison of the Efficacy Among Transcatheter Arterial Chemoembolization (TACE)-Radiofrequency Ablation Plus Apatinib, TACE Plus Apatinib, and TACE Alone for Hepatocellular Carcinoma: A Retrospective Study

BACKGROUND

This study aimed to investigate the efficacy and safety of apatinib plus transarterial chemoembolization (TACE) and radiofrequency ablation (RFA) in the therapy of hepatocellular carcinoma (HCC) patients.

METHODS

From December 2015 to June 2018, 175 eligible participants were included in our research. Twenty-four patients who received apatinib plus TACE and RFA were categorized as the TACE + RFA-A group, 82 patients who received apatinib plus TACE were categorized as the TACE-A group, and 69 patients who received TACE alone were categorized as the TACE group. Treatment complications, treatment response, overall survival (OS), and time to progression (TTP) were recorded. Survival analyses were compared. Univariate and multivariate Cox analyses were conducted to investigate the predictive factors for OS and TTP. A subgroup analysis was carried out.

RESULTS

The median TTP was 8.0 months (95% CI 6.7-9.3) in the TACE + RFA-A, which was longer than the TACE-A group (6.0 months, 95% CI 4.8-7.2) and TACE group (3.0 months, 95% CI 2.3-3.7); the difference was statistically significant (P < 0.001). The median OS was 23.0 months (95% CI 12.6-33.4) in the TACE + RFA-A group, 18.0 months (95% CI 16.2-19.8) in the TACE-A group, and 8.0 months (95% CI 5.3-10.7) in the TACE group; the difference was statistically significant (P < 0.001). The objective response rate (ORR) was higher in TACE + RFA-A t group (M1, 70.8% vs 65.9% vs. 46.4%, P = 0.023; M3, 58.3% vs. 53.7% vs. 26.1%, P = 0.001). Multivariate Cox analysis demonstrated that treatment strategy and tumor size were independent prognostic factors for the OS and TTP, whereas the Child-Pugh stage was predictive factor of OS. No treatment-related death was observed. The toxicity was comparable between the two groups.

CONCLUSION

TACE combined with RFA plus apatinib is a safe three-modality treatment for the intermediate or advanced HCC, and it demonstrated better efficacy than TACE plus apatinib or TACE alone.

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).

Targeting PI3Kγ/AKT Pathway Remodels LC3-Associated Phagocytosis Induced Immunosuppression After Radiofrequency Ablation

Residual tumors after insufficient radiofrequency ablation (IRFA) shows accelerated progression and anti-PD-1 resistance. It is also reported that macrophages infiltrating into residual tumors leads to anti-PD-1 resistance. Elements of autophagy have been detected to conjugate LC3 to be increasingly expressed in residual tumors. The underlying mechanisms between LC3 and macrophages are aimed to be investigated, and explore further ways to enhance immunotherapy in treating residual tumors. In mice models and patients, macrophages demonstrate increased infiltration into residual tumors, especially surrounding the ablated zone. Single-cell transcriptome demonstrates enhancement of immunosuppression function in macrophages after IRFA. It is shown that macrophages engulf heat-treated cells through LC3-associated phagocytosis (LAP), enhance IL-4 mediated macrophage programming through the PI3Kγ/AKT pathway, and suppress T cell proliferation. Blockade of the PI3Kγ/AKT pathway enhances the antitumor activity of PD-1 blockades, inhibits malignant growth, and enhances survival in post-IRFA models. In conclusion, in mice models and patients, macrophages demonstrate increased infiltration around ablated zones in residual tumors. Blockade of the PI3Kγ/AKT pathway suppresses the growth of residual tumors in subcutaneous and orthotopic models. The results illustrate the translational potential of PI3Kγ inhibitors to enhance anti-PD-1 therapy for the treatment of residual tumors after IRFA.

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.

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.

A combined miR-34a and arsenic trioxide nanodrug delivery system for synergistic inhibition of HCC progression after microwave ablation

Background

Microwave ablation (MWA) has become an alternative treatment for unresectable hepatocellular carcinoma (HCC), but it does not eliminate the risk of recurrence and metastasis after treatment. Recent studies have demonstrated that miR-34a presents decreased gene expression in residual tumours after ablation therapy and can increase the therapeutic effect of arsenic trioxide against HCC, which brings new opportunities for HCC treatment.

Methods

A pH-sensitive charge inversion material was used to construct a nanotargeted delivery system based on the synergistic effects of miR-34a and As2O3. We established in vitro and in vivo models of HCC microwave ablation and performed in-depth research on the dual-drug system to inhibit the rapid progression and induce pyroptosis in HCC cells after microwave ablation.

Results

The antitumour effects were enhanced with the dual-drug nanoparticles relative to the single-drug formulations, and the therapeutic efficacy of the nanoparticles was more significant in a weakly acidic environment. The dual-drug nanoparticles increased the N-terminal portion of GSDME and decreased the expression of Cyt-c and c-met.

Conclusions

Dual-drug nanoparticles may improve the therapeutic efficacy of HCC treatment after insufficient ablation through Cyt-c and GSDME-N and decrease the expression levels of c-met. These nanoparticles are expected to provide new treatment methods for residual HCC after MWA, prolong the survival of patients and improve their quality of life.

Interventional Radiology Image-Guided Locoregional Therapies (LRTs) and Immunotherapy for the Treatment of HCC

Image-guided locoregional therapies (LRTs) are a crucial asset in the treatment of hepatocellular carcinoma (HCC), which has proven to be characterized by an impaired antitumor immune status. LRTs not only directly destroy tumor cells but also have an immunomodulating role, altering the tumor microenvironment with potential systemic effects. Nevertheless, the immune activation against HCC induced by LRTs is not strong enough on its own to generate a systemic significant antitumor response, and it is incapable of preventing tumor recurrence. Currently, there is great interest in the possibility of combining LRTs with immunotherapy for HCC, as this combination may result in a mutually beneficial and synergistic relationship. On the one hand, immunotherapy could amplify and prolong the antitumoral immune response of LRTs, reducing recurrence cases and improving outcome. On the other hand, LTRs counteract the typical immunosuppressive HCC microenvironment and status and could therefore enhance the efficacy of immunotherapy. Here, after reviewing the current therapeutic options for HCC, we focus on LRTs, describing for each of them the technique and data on its effect on the immune system. Then, we describe the current status of immunotherapy and finally report the recently published and ongoing clinical studies testing this combination.

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.

Sublethal heat stress-induced O-GlcNAcylation coordinates the Warburg effect to promote hepatocellular carcinoma recurrence and metastasis after thermal ablation

The malignant transformation of residual hepatocellular carcinoma (HCC) cells after thermal ablation is considered as the main factor promoting postoperative HCC progression, which greatly limits the improvement of long-term survival, and at present there is no effective targeted therapeutic strategies. The Warburg effect is a metabolic feature correlated highly with malignant transformation (e.g. epithelial-to-mesenchymal transition [EMT]). Here, we showed that sublethal heat stress triggered a stronger Warburg effect of HCC cells, which contributed to the thermotolerance and invasion of HCC cells. Sublethal heat stress-induced O-GlcNAcylation was involved in this process. Such enhanced Warburg effect in HCC cells may be eliminated through O-GlcNAcylation inhibition, resulting in impaired thermotolerance and EMT, and thereby preventing tumor recurrence and metastasis of HCC-bearing mice after insufficient thermal ablation. Finally, we present evidence that sublethal heat stress-induced O-GlcNAcylation regulates the Warburg effect in HCC cells by promoting hypoxia-inducible factor 1α (HIF-1α) stability. In conclusion, the present study suggests that O-GlcNAcylation coordinates the Warburg effect to promote HCC progression after thermal ablation, which may serve as a novel potential target for controlling postoperative HCC recurrence and metastasis.

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.

Periprocedural risk factors for incomplete radiofrequency ablation of liver metastases from colorectal cancer: a single-center retrospective analysis

OBJECTIVE

To explore independent risk factors for incomplete radiofrequency ablation (iRFA) of colorectal cancer liver metastases (CRLM) and evaluate adverse outcomes following iRFA.

MATERIALS AND METHODS

Magnetic resonance imaging data of CRLM patients who received percutaneous RFA were randomized into training (70%) and validation set 1 (30%) data sets. An independent validation set 2 was derived from computed tomography scans. Uni- and multivariate analyses identified independent risk factors for iRFA. Area under the curve (AUC) values were used to evaluate the predictive model performance. Risk points were assigned to independent predictors, and iRFA was predicted according to the total risk score. Kaplan-Meier curves were used to assess new intrahepatic metastases (NIHM), unablated tumor progression, and overall survival (OS).

RESULTS

Multivariate regression determined as independent iRFA risk factors perivascular tumor location, subcapsular tumor location, tumor size ≥20 mm, and minimal ablative margin ≤5 mm. The AUC values of the model in the training set, validation set 1, and validation set 2 were 0.867, 0.772, and 0.820, respectively. The respective AUC values of the total risk score were 0.864, 0.768, and 0.817. During the 6-year follow-up, the cumulative OS was significantly shorter in the iRFA than in the complete RFA group, and NIHM (hazard ratio [HR] = 2.79; 95% confidence interval [CI]: 1.725, 4.513) and unablated tumor progression (HR = 3.473; 95% CI: 1.506, 8.007) were more severe.

CONCLUSIONS

Perivascular tumor location, subcapsular tumor location, tumor size ≥20 mm, and minimal ablative margin ≤5 mm were independent risk factors for iRFA. iRFA may be a potential predictor of NIHM, unablated tumor progression, and OS.

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.

Comparison of Percutaneous Radiofrequency Ablation for Subcapsular and Non-Subcapsular Colorectal Cancer Liver Metastases

Purpose

To evaluate the efficacy and safety of percutaneous radiofrequency ablation (RFA) for subcapsular colorectal cancer liver metastases (CLMs).

Materials and Methods

With the approval of the Institutional Review Board, the clinical data of CLM patients who underwent percutaneous RFA for the first time from August 2010 to August 2020 were continuously collected. All CLMs were divided into subcapsular and non-capsular groups. Baseline characteristic data, technical effectiveness, minimal ablative margin, complications, local tumor progression (LTP), and overall survival (OS) between the two groups were analyzed using the t-test or chi-square test. A Cox regression model was used to evaluate the prognostic factors of LTP.

Results

One hundred and ninety-nine patients (124 males; mean age, 60.2 years) with 402 CLMs (221 subcapsular; mean size, 16.0 mm) were enrolled in the study. Technical effectiveness was achieved in 93.5% (376/402) of CLMs, with a major complication rate of 5.5%. Compared with non-subcapsular tumors, the minimal ablative margin achieved in subcapsular CLM was smaller (χ² = -8.047, P < 0.001). With a median follow-up time of 23 months (range, 3−96 months), 37.1% of the tumors had LTP. The estimated cumulative OS at 1, 3, and 5 years was 96.1%, 66.0%, and 44.2%, respectively. There were no statistically significant differences between the two groups in terms of technical effectiveness (χ² = 0.484, P = 0.487), major complications (χ² = 0.082, P = 0.775), local tumor progression-free survival (LTPFS) (χ² = 0.881, P = 0.348), and OS (χ² = 2.874, P = 0.090). Minimal ablative margin, tumor size (≥20 mm), and technical effectiveness were predictors of LTP (all P < 0.05).

Conclusion

RFA is a safe and effective technique for local tumor control of subcapsular CLMs.

Autophagy in liver diseases

Autophagy is the liver cell energy recycling system regulating a variety of homeostatic mechanisms. Damaged organelles, lipids and proteins are degraded in the lysosomes and their elements are re-used by the cell. Investigations on autophagy have led to the award of two Nobel Prizes and a health of important reports. In this review we describe the fundamental functions of autophagy in the liver including new data on the regulation of autophagy. Moreover we emphasize the fact that autophagy acts like a two edge sword in many occasions with the most prominent paradigm being its involvement in the initiation and progress of hepatocellular carcinoma. We also focused to the implication of autophagy and its specialized forms of lipophagy and mitophagy in the pathogenesis of various liver diseases. We analyzed autophagy not only in well studied diseases, like alcoholic and nonalcoholic fatty liver and liver fibrosis but also in viral hepatitis, biliary diseases, autoimmune hepatitis and rare diseases including inherited metabolic diseases and also acetaminophene hepatotoxicity. We also stressed the different consequences that activation or impairment of autophagy may have in hepatocytes as opposed to Kupffer cells, sinusoidal endothelial cells or hepatic stellate cells. Finally, we analyzed the limited clinical data compared to the extensive experimental evidence and the possible future therapeutic interventions based on autophagy manipulation.

Thermally sensitive fluorescence imaging system for radiofrequency ablation guidance

Radiofrequency ablation (RFA) has been clinically used as a minimally invasive procedure for the treatment of many solid tumors. However, the current imaging techniques have some shortages in RFA guidance, especially for the assessment of the margin of ablation. Herein, we developed a novel optical imaging platform to guide RFA utilizing fluorescence resonance energy transfer from a thermally sensitive fluorescent protein conjugated to a near-infrared fluorescent dye. Additionally, attaching receptor-targeting ligands further equipped the system with high specificity to tumors overexpressing the targeted receptor.

Inflammation induced by incomplete radiofrequency ablation accelerates tumor progression and hinders PD-1 immunotherapy

Radiofrequency ablation (RFA) promotes tumor antigen-specific T cell responses and enhances the effect of immunotherapy in preclinical settings. Here we report that the existence of remnant tumor masses due to incomplete RFA (iRFA) is associated with earlier new metastases and poor survival in patients with colorectal cancer liver metastases (CRCLM). Using mouse models, we demonstrate that iRFA promotes tumor progression and hinders the efficacy of anti-PD-1 therapy. Immune analysis reveals that iRFA induces sustained local inflammation with predominant myeloid suppressor cells, which inhibit T cell function in tumors. Mechanistically, tumor cell-derived CCL2 is critical for the accumulation of monocytes and tumor-associated macrophages (TAMs). The crosstalk between TAMs and tumor cells enhances the CCL2 production by tumor cells. Furthermore, we find that administration of a CCR2 antagonist or the loss of CCL2 expression in tumor cells enhances the antitumor activity of PD-1 blockade, providing a salvage alternative for residual tumors after iRFA.

Radiofrequency ablation is used to treat metastatic colorectal cancer. In this study, the authors show that incomplete ablation of tumours results in metastases and show in mouse models that the chemokine CCL2 recruits myeloid cells to the partially ablated tumours, which can block T cell function.

Lower Extremity Paralysis After Radiofrequency Ablation of Vertebral Metastases

BACKGROUND

Radiofrequency ablation (RFA) focally destroys abnormal or dysfunctional tissue using thermal energy generated from alternating current. The utilization of RFA has gained popularity as a minimally invasive procedure for the treatment of skeletal metastases with a particular focus on palliative pain treatments to the spine, pelvis, long bones, sternum, and glenoid. More recently, single-session procedures that combine RFA with vertebral augmentation techniques have allowed treatment to areas of pain associated with pathologic fractures secondary to metastatic disease. Although many studies have been done to investigate the safety and efficacy of RFA, there have been no reported cases to date in which the use of RFA for the treatment of spinal metastases has led to any major permanent neurological injury.

CASE DESCRIPTION

This report describes a case of a 61-year-old woman who underwent RFA and kyphoplasty for spinal metastases and noted the immediate onset of lower extremity paralysis after the procedure. To the best of our knowledge, this is the first documented case of permanent lower extremity paralysis in the medical literature after radiofrequency thermal ablation of spine metastases.

CONCLUSIONS

Postoperative magnetic resonance imaging and physical examination suggest RFA-induced thermal injury as the most likely mechanism of paralysis. In this report, a review of previous in vivo models used in studying the efficacy and safety of spine RFA is conducted. Additionally, the literature has been reviewed for any neurological events reported with the use of RFA in the treatment of patients with vertebral pathology.

Insufficient radiofrequency ablation-induced autophagy contributes to the rapid progression of residual hepatocellular carcinoma through the HIF-1α/BNIP3 signaling pathway

Currently speaking, it is noted that radiofrequency ablation (RFA) has been the most widely used treatment for hepatocellular carcinoma (HCC) occurring in patients. However, accumulating evidence has demonstrated that the incidence of insufficient RFA (IRFA) may result in the identified rapid progression of residual HCC in the patient, which can greatly hinder the effectiveness and patient reported benefits of utilizing this technique. Although many efforts have been proposed, the underlying mechanisms triggering the rapid progression of residual HCC after IRFA have not yet been fully clarified through current research literature reviews. It was shown in this study that cell proliferation, migration and invasion of residual HepG2 and SMMC7721 cells were significantly increased after the IRFA was simulated in vitro. In other words, it is noted that IRFA could do this by enhancing the image of autophagy of the residual HCC cell via the HIF-1α/BNIP3 pathway. Consequently, the down-regulation of BNIP3 may result in the inhibition of the residual HCC cell progression and autophagy after IRFA. Our present study results suggest that IRFA could promote residual HCC cell progression in vitro by enhancing autophagy via the HIF-1α/BNIP3 pathway. For this reason, it is noted that the targeting of the BNIP3 may be useful in preventing the rapid growth and metastasis of residual HCC after IRFA.

Functional variants of autophagy-related genes are associated with the development of hepatocellular carcinoma

AIMS

Hepatocellular carcinoma (HCC) is the most common primary liver cancer, and accounts for substantial morbidity and mortality. Autophagy plays an essential role in the development and progression of HCC. This study aims to evaluate whether genetic variants in autophagy-related genes (ATGs) affect the development of HCC.

MATERIALS AND METHODS

We conducted a case-control study with 986 HCC cases and 1000 healthy controls to analyze 14 functional variants of five ATGs (ATG3, ATG5, ATG10, ATG12 and ATG16L1) among a Chinese population.

KEY FINDINGS

We found ATG5 rs17067724 (G vs A: OR = 0.80; 95% CI = 0.65-0.98; P = 0.031), ATG10 rs1864183 (G vs A: OR = 1.29; 95% CI = 1.07-1.57; P = 0.009), ATG10 rs10514231 (C vs T: OR = 1.41; 95% CI = 1.15-1.73; P = 0.001), ATG12 rs26537 (C vs T: OR = 1.16; 95% CI = 1.02-1.33; P = 0.030), and ATG16L1 rs4663402 (T vs A: OR = 1.28; 95% CI = 1.01-1.63; P = 0.044) were significantly associated with HCC risk. Specifically, ATG10 rs10514231 kept significant association even adjusted for Bonferroni correction (P = 0.001 × 14 = 0.014). Bioinformatics analyses showed that allele C of ATG10 rs10514231 was significantly correlated with higher expression of ATG10 gene in both HCC tissues and normal liver tissues. Dual-luciferase reporter assay presented that cell lines transfected with vectors containing the risk allele C of rs10514231 showed higher relative luciferase activity compared to that containing the allele T.

SIGNIFICANCE

These results suggested that ATG10 rs10514231 might contribute to an allele-specific effect on the expression of host gene ATG10 and explain a fraction of HCC genetic susceptibility. Our study would benefit the construction of early warning model, early prevention, screening, even therapeutic target of HCC.

Autophagy in liver diseases: Time for translation?

Autophagy is a self-eating catabolic pathway that contributes to liver homeostasis through its role in energy balance and in the quality control of the cytoplasm, by removing misfolded proteins, damaged organelles and lipid droplets. Autophagy not only regulates hepatocyte functions but also impacts on non-parenchymal cells, such as endothelial cells, macrophages and hepatic stellate cells. Deregulation of autophagy has been linked to many liver diseases and its modulation is now recognized as a potential new therapeutic strategy. Indeed, enhancing autophagy may prevent the progression of a number of liver diseases, including storage disorders (alpha-1 antitrypsin deficiency, Wilson's disease), acute liver injury, non-alcoholic steatohepatitis and chronic alcohol-related liver disease. Nevertheless, in some situations such as fibrosis, targeting specific liver cells must be considered, as autophagy displays opposing functions depending on the cell type. In addition, an optimal therapeutic time-window should be identified, since autophagy might be beneficial in the initial stages of disease, but detrimental at more advanced stages, as in the case of hepatocellular carcinoma. Finally, identifying biomarkers of autophagy and methods to monitor autophagic flux in vivo are important steps for the future development of personalized autophagy-targeting strategies. In this review, we provide an update on the regulatory role of autophagy in various aspects of liver pathophysiology, describing the different strategies to manipulate autophagy and discussing the potential to modulate autophagy as a therapeutic strategy in the context of liver diseases.

Tumor Location Influences Oncologic Outcomes of Hepatocellular Carcinoma Patients Undergoing Radiofrequency Ablation

Radiofrequency ablation (RFA) is recommended as a first-line therapy for small hepatocellular carcinoma (HCC). Tumor location is a potential factor influencing the procedure of RFA. To compare oncologic outcomes of RFA for different tumor locations, this retrospective study enrolled 194 patients with small HCC who had undertaken RFA. The HCC nodules were classified as peri-hepatic-vein (pHV) or non-pHV, peri-portal-vein (pPV) or non-pPV, and subcapsular or non-subcapsular HCC. The regional recurrence-free survival (rRFS), overall survival (OS), recurrence-free survival (recurrence in any location, RFS) and distant recurrence-free survival (dRFS) were compared. Operation failures were recorded in five pPV HCC patients, which was more frequent than in non-pPV HCC patients (p = 0.041). The 1-, 3-, and 5-year rRFS was 68.7%, 53.7%, and 53.7% for pHV patients and 85.1%, 76.1%, and 71.9% for non-pHV patients, respectively (p = 0.012). After propensity score matching, the 1-, 3-, and 5-year rRFS was still worse than that of non-pHV patients (p = 0.013). The OS, RFS, and dRFS were not significantly different between groups.

CONCLUSIONS

A pHV location was a risk factor for the regional recurrence after RFA in small HCC patients. The tumor location may not influence OS, RFS, and dRFS. Additionally, a pPV location was a potential high-risk factor for incomplete ablation.