Heat Stress and Hepatic Laser Thermal Ablation Induce Hepatocellular Carcinoma Growth: Role of PI3K/mTOR/AKT Signaling

The Impact of Microwave Ablation on Recurrence and Metastasis of Hepatocellular Carcinoma: Insights From Animal Studies and Cytokine Profiling

Background

Microwave ablation (MWA) is commonly used to treat hepatocellular carcinoma (HCC), but its effects on normal liver tissue and tumors remain unclear. While MWA causes direct tumor destruction, it also induces inflammatory responses in the surrounding liver tissue, which may influence tumor progression, metastasis, and recurrence. The role of cytokine alterations in this post-ablation inflammatory microenvironment is crucial for understanding how MWA impacts tumor behavior.

Purpose

This study aims to investigate the impact of post-ablation inflammatory responses on HCC recurrence and metastasis through animal experiments and cytokine profiling, with the goal of identifying potential biomarkers or therapeutic targets.

Materials and Methods

This study involved 35 male C57BL/6 mice (6-8 weeks old) to establish metastatic and orthotopic cancer models. The effects of normal liver tissue ablation and HCC ablation on tumor metastasis and recurrence were investigated. Cytokine expression changes were assessed using the Proteome Profiler Mouse XL Cytokine Array, and prognostic implications were analyzed using the TCGA database. Multiple group comparisons assessed using the Mann-Whitney U-test. Statistical significance was defined as a two-tailed p-value less than 0.05.

Results

Microwave ablation of normal liver tissue promotes intrahepatic metastasis of HCC. Incomplete ablation of liver tumors accelerates intrahepatic or pulmonary metastasis. Post-ablation, increased expression of MMP-9, OPN, VEGF, CHI3L1, AREG, CXCL2, and IL-1α in the peritumoral region suggests a shift toward a pro-inflammatory and pro-metastatic microenvironment, potentially facilitating tumor cell invasion, angiogenesis, and immune evasion.

Conclusion

HCC recurrence and metastasis following ablation may be driven by cytokine-mediated changes in the tumor microenvironment. Targeting key cytokines such as MMP-9, OPN, and CHI3L1 could provide new strategies for improving post-ablation outcomes and reducing recurrence rates in clinical settings.

Histone lactylation drives liver cancer metastasis by facilitating NSF1-mediated ferroptosis resistance after microwave ablation

Insufficient microwave ablation (IMWA) is linked to aggressive hepatocellular carcinoma (HCC) progression. An increase in lactate levels after sublethal heat stress (HS) has been confirmed in HCC. However, the role of lactate-related histone lactylation in the progression of HCC caused by sublethal HS remains unclear. Here, we found that the metastatic potential of HCC increased in a lactate-dependent manner after IMWA. Moreover, sublethal HS triggered an increase in H3K18la modification, as validated in a cell-derived xenograft mouse model and human HCC samples. By performing an integrated analysis of proteomic and transcriptomic profiles, we revealed that HCC cells exhibited increased intracellular iron ion homeostasis and developed resistance to platinum-based drugs after exposure to sublethal HS. We subsequently integrated proteomic and transcriptomic data with H3K18la-specific chromatin immunoprecipitation (ChIP) sequencing to identify candidate genes involved in sublethal heat treatment-induced HCC cell metastasis. Mechanically, an increase in H3K18la modification enhanced the transcriptional activity of NFS1 cysteine desulfurase (NFS1), a key player in iron‒sulfur cluster biosynthesis, thereby reducing the susceptibility of HCC to ferroptosis after IMWA. Knocking down NFS1 diminished the metastatic potential of sublethally heat-treated HCC cells. Additionally, NFS1 deficiency exhibited a synergistic effect with oxaliplatin, leading to the significant inhibition of the metastatic capability of HCC cells both in vitro and in vivo, regardless of sublethal HS treatment. In conclusion, our study revealed the oncogenic role of histone lactylation in HCC after IMVA. We also bridged histone lactylation with ferroptosis, providing novel therapeutic targets for HCC following microwave ablation, particularly when combined with oxaliplatin-based chemotherapy.

The XIAP inhibitor AZD5582 improves the treatment effect of microwave ablation on hepatocellular carcinoma

Background and purpose

Microwave ablation (MWA) is one of the first-line therapy recommended for early-stage hepatocellular carcinoma (HCC). However, the residual tumor, resulting from insufficient ablation, led to recurrence and metastasis of liver cancer. Novel combination strategies are urgently needed to enhance efficiency of MWA.

Methods

We detected the expression of XIAP protein after ablation in primary liver cancer patients using immunohistochemistry. Then, we established in vitro and in vivo IMWA models to further detect XIAP expression. We established an in vitro IMWA model by heating HCC cell lines and, at the same time, applied the XIAP inhibitor AZD5582 and verified the proliferation, migration, and pro-apoptotic ability of the XIAP inhibitor on tumor cells using CCK8, colony formation assay, cell scratch assay, and flow cytometry flow. The IMWA model of C57BL/6 and NTG mice were established, and AZD5582 was used in combination to evaluate the inhibitory and pro-apoptotic effects of different treatment regimens on tumor growth and to detect the local immune infiltration of C57BL/6 tumors. Finally, AZD5582 drug toxicity was detected to confirm its feasibility.

Results

XIAP protein expression is significantly increased in recurrent hepatocellular carcinoma tissues of patients who previously received microwave ablation therapy. In vitro experiments showed that the migration and proliferation ability of HCC cells was significantly reduced, and the level of apoptosis was increased after application of the XIAP inhibitor AZD5582. In vivo experiments further confirmed that ablation combined with the application of AZD5582 significantly reduced the proliferation ability of residual hepatocellular carcinoma. Concurrently, in C57 BL/6 mice with AZD5582 application, the level of local CD8+ T-cell infiltration in the tumor was increased, while the level of Foxp3+ regulatory T-cell infiltration was significantly reduced. The low toxicity of AZD5582 was further confirmed through hematological and pathological examinations of vital organs. These results provide new clues for hepatocellular carcinoma treatment, suggesting the potential role of XIAP inhibitors in hepatocellular carcinoma treatment and their impact in immunomodulation.

Conclusions

In this study, we found that the XIAP inhibitor AZD5582 modulates the immune microenvironment and inhibits the progression of post-ablation residual hepatocellular carcinoma.

The immune response of hepatocellular carcinoma after locoregional and systemic therapies: The available combination option for immunotherapy

Hepatocellular carcinoma (HCC) is associated with a highly heterogeneous immune environment that produces an immune response to various locoregional treatments (LRTs), which in turn affects the effectiveness of immunotherapy. Although LRTs still dominate HCC therapies, 50-60% of patients will ultimately be treated with systemic therapies and might receive those treatments for the rest of their life. TACE, SIRT, and thermal ablation can dramatically increase the immunosuppressive state of HCC, a condition that can be addressed by combination with immunotherapy to restore the activity of lymphocytes and the secretion of cellular immune factors. Immune treatment with locoregional and systemic treatments has dramatically changed the management of HCC. In this review, we examine the research on the changes in the immune microenvironment after locoregional or systemic treatment. We also summarize the regulation of various immune cells and immune factors in the tumor microenvironment and discuss the different infiltration degrees of immune cells and factors on the prognosis of HCC to better compare the efficacy between different treatment methods from the perspective of the tumor microenvironment. This information can be used to help develop treatment options for the upcoming new era of HCC treatment in the future.

Radiofrequency Ablation-Induced Tumor Growth Is Suppressed by MicroRNA-21 Inhibition in Murine Models of Intrahepatic Colorectal Carcinoma

PURPOSE

To investigate the role of microRNA-21 (miR21) in radiofrequency (RF) ablation-induced tumor growth and whether miR21 inhibition suppresses tumorigenesis.

MATERIAL AND METHODS

Standardized liver RF ablation was applied to 35 C57/BL6 mice. miR21 and target proteins pSTAT3, PDCD4, and PTEN were assayed 3 hours, 24 hours, and 3 days after ablation. Next, 53 Balb/c and 44 C57BL/6 mice received Antago-miR21 or scrambled Antago-nc control, followed by intrasplenic injection of 10,000 CT26 or MC38 colorectal tumor cells, respectively. Hepatic RF ablation or sham ablation was performed 24 hours later. Metastases were quantified and tumor microvascular density (MVD) and cellular proliferation were assessed at 14 or 21 days after the procedures, respectively.

RESULTS

RF ablation significantly increased miR21 levels in plasma and hepatic tissue at 3 and 24 hours as well as target proteins at 3 days after ablation (P < .05, all comparisons). RF ablation nearly doubled tumor growth (CT26, 2.0 SD ± 1.0 fold change [fc]; MC38, 1.9 SD ± 0.9 fc) and increased MVD (CT26, 1.9 SD ± 1.0 fc; MC38, 1.5 ± 0.5 fc) and cellular proliferation (CT26, 1.7 SD ± 0.7 fc; MC38, 1.4 SD ± 0.5 fc) compared with sham ablation (P < .05, all comparisons). RF ablation-induced tumor growth was suppressed when Antago-miR21 was administered (CT26, 1.0 SD ± 0.7 fc; MC38, 0.9 SD ± 0.4 fc) (P < .01, both comparisons). Likewise, Antago-miR21 decreased MVD (CT26, 1.0 SD ± 0.3 fc; MC38, 1.0 SD ± 0.2 fc) and cellular proliferation (CT26, 0.9 SD ± 0.3 fc; MC38, 0.8 SD ± 0.3 fc) compared with baseline (P < .05, all comparisons).

CONCLUSIONS

RF ablation upregulates protumorigenic miR21, which subsequently influences downstream tumor-promoting protein pathways. This effect can potentially be suppressed by specific inhibition of miR21, rendering this microRNA a pivotal and targetable driver of tumorigenesis after hepatic thermal ablation.

Fibroblast growth factors induce hepatic tumorigenesis post radiofrequency ablation

Image-guided radiofrequency ablation (RFA) is used to treat focal tumors in the liver and other organs. Despite potential advantages over surgery, hepatic RFA can promote local and distant tumor growth by activating pro-tumorigenic growth factor and cytokines. Thus, strategies to identify and suppress pro-oncogenic effects of RFA are urgently required to further improve the therapeutic effect. Here, the proliferative effect of plasma of Hepatocellular carcinoma or colorectal carcinoma patients 90 min post-RFA was tested on HCC cell lines, demonstrating significant cellular proliferation compared to baseline plasma. Multiplex ELISA screening demonstrated increased plasma pro-tumorigenic growth factors and cytokines including the FGF protein family which uniquely and selectively activated HepG2. Primary mouse and immortalized human hepatocytes were then subjected to moderate hyperthermia in-vitro, mimicking thermal stress induced during ablation in the peri-ablational normal tissue. Resultant culture medium induced proliferation of multiple cancer cell lines. Subsequent non-biased protein array revealed that these hepatocytes subjected to moderate hyperthermia also excrete a similar wide spectrum of growth factors. Recombinant FGF-2 activated multiple cell lines. FGFR inhibitor significantly reduced liver tumor load post-RFA in MDR2-KO inflammation-induced HCC mouse model. Thus, Liver RFA can induce tumorigenesis via the FGF signaling pathway, and its inhibition suppresses HCC development.

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.

DNAJC24 is a potential therapeutic target in hepatocellular carcinoma through affecting ammonia metabolism

Evolutionarily conserved heat shock proteins are involved in the heat shock response of cells in response to changes in the external environment. In normal tissues, heat shock proteins can help cells survive in a rapidly changing environment. Likewise, in malignant tumors heat shock proteins may help tumor cells cope with external stresses as well as the stress of treatment. In this way they become accomplices of malignant tumors. Here we demonstrated for the first time that high expression of DNAJC24 (a heat shock protein) shortens survival in patients with HCC by immunohistochemical staining of 167 paired hepatocellular carcinomas and paraneoplastic tissues as well as data from public databases. In vitro experiments demonstrated that stimuli such as hypoxia, starvation and heat could upregulate DNAJC24 expression in HCC cells through transcriptional regulation of HSF2, and high expression of DNAJC24 in HCC cells could promote the proliferation and motility of HCC cells. In addition, we also verified that targeting DNAJC24 under normal culture conditions can affect the proliferation and autophagy of HCC cells by interfering with ammonia metabolism, thereby inhibiting the malignant progression of HCC. Overall, we suggested that DNAJC24 may become a new target for the treatment of HCC.

HIF-2α-targeted interventional chemoembolization multifunctional microspheres for effective elimination of hepatocellular carcinoma

Transcatheter arterial chemoembolization (TACE) is widely used for the treatment of advanced hepatocellular carcinoma (HCC). However, the long-term hypoxic microenvironment caused by TACE seriously affects the therapeutic effect of TACE. HIF-2α plays a crucial role on the chronic hypoxia process, which might be an ideal target for TACE therapy. Herein, a multifunctional polyvinyl alcohol (PVA)/hyaluronic acid (HA)-based microsphere (PT/DOX-MS) co-loaded with doxorubicin (DOX) and PT-2385, an effective HIF-2α inhibitor, was developed for enhanced TACE treatment efficacy. In vitro and in vivo studies revealed that PT/DOX-MS had a superior ability to treat HCC by blocking the tumor cells in G2/M phase, prompting cell apoptosis, and inhibiting tumor angiogenesis. The antitumor mechanisms of PT/DOX-MS were possibly due to that the introduction of PT-2385 could effectively inhibit the expression level of HIF-2α in hypoxic HCC cells, thereby down-regulating the expression levels of Cyclin D1, VEGF and TGF-α. In addition, the combination of DOX and PT-2385 could jointly inhibit VEGF expression, which was another reason accounting for the combined anti-cancer effect of PT/DOX-MS. Overall, our study demonstrated that PT/DOX-MS is a promising embolic agent for enhanced HCC treatment via the combined effect of hypoxia microenvironment improvement, chemotherapy, and embolization.

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.

Initial Incomplete Thermal Ablation Is Associated With a High Risk of Tumor Progression in Patients With Hepatocellular Carcinoma

Purpose

To investigate whether incomplete thermal ablation is associated with a high risk of tumor progression in patients with hepatocellular carcinoma (HCC), and to compare the efficacy of repeated thermal ablation and transarterial chemoembolization (TACE) for residual tumor after incomplete ablation.

Methods

This retrospective study included 284 patients with unresectable HCC who underwent thermal ablation from June 2014 to September 2020. The response of the initially attempted ablation was classified into complete (n=236) and incomplete (n=48). The progression-free survival (PFS) and overall survival (OS) were compared between patients with complete and incomplete responses, before and after a one-to-one propensity score-matching (PSM), and between patients in whom repeated ablation or TACE was performed after a first attempt incomplete ablation.

Results

After PSM of the 284 patients, 46 pairs of patients were matched. The PFS was significantly higher in the complete response group than in the incomplete response group (P<0.001). No difference in OS was noted between two groups (P=0.181). After a first attempt incomplete ablation, 29 and 19 patients underwent repeated ablation and TACE, respectively. There were no significant differences in PFS (P=0.424) and OS (P=0.178) between patients who underwent repeated ablation and TACE. In multivariate Cox regression analysis, incomplete response (P<0.001) and Child-Pugh class B (P=0.017) were independent risk factors for tumor progression, while higher AFP level (P=0.011) and Child-Pugh class B (P=0.026) were independent risk factors for poor OS.

Conclusion

Although patients with incomplete ablation are associated with tumor progression compared with those with complete ablation, their OS is not affected by incomplete ablation. When patients present with residual tumors, TACE may be an alternative if repeated ablation is infeasible.

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.

Risk Factors, Patterns, and Long-Term Survival of Recurrence After Radiofrequency Ablation With or Without Transarterial Chemoembolization for Hepatocellular Carcinoma

Objectives

To classify hepatocellular carcinoma (HCC) recurrence patterns after radiofrequency ablation (RFA) or transarterial chemoembolization (TACE) combined with RFA (TACE-RFA) and analyze their risk factors and impacts on survival.

Methods

We retrospectively evaluated the medical records of HCC patients who underwent RFA or TACE-RFA from January 2006 to December 2016. HCC recurrences were classified into four patterns: local tumor progression (LTP), intra-segmental recurrence, extra-segmental recurrence, and aggressive recurrence. Risk factors, overall survival (OS), and post-recurrence survival of each pattern were evaluated.

Results

A total of 249 patients with a single, hepatitis-B virus (HBV)-related HCC ≤ 5.0 cm who underwent RFA (HCC ≤ 3.0 cm) or TACE-RFA (HCC of 3.1-5.0 cm) were included. During follow-up (median, 53 months), 163 patients experienced HCC recurrence: 40, 43, 62 and 18 patients developed LTP, intra-segmental recurrence, extra-segmental recurrence, and aggressive recurrence, respectively; the median post-recurrence survival was 49, 37, 25 and 15 months, respectively (P < .001); the median OS was 65, 56, 58 and 28 months, respectively (P < .001). Independent risk factors for each pattern were as follows: tumor sized 2.1-3.0 cm undergoing RFA alone and insufficient ablative margin for LTP, periportal tumor and non-smooth tumor margin for intra-segmental recurrence, HBV-DNA ≥ 2000 IU/mL for extra-segmental recurrence, and periportal tumor and α-fetoprotein ≥ 100 ng/mL for aggressive recurrence. Recurrence pattern (P < .001) and Child-Pugh class B (P = .025) were independent predictors for OS.

Conclusions

Based on our classification, each recurrence pattern had different recurrence risk factors, OS, and post-recurrence survival.

Thermal Ablation for Papillary Thyroid Microcarcinoma: How Far We Have Come?

Purpose

Thermal ablation (TA), as one of the most currently remarkable technologies, has achieved great success in many malignant diseases including but not limited to hepatic and renal carcinoma. In recent years, this technology was gradually introduced to the treatment of papillary thyroid microcarcinoma (PTMC) and even papillary thyroid carcinoma (PTC). Thereby, we summarized the current progress of TA development in the treatment of PTMC.

Methods

The latest relevant literature from the PubMed database with keywords "thermal ablation", "papillary thyroid microcarcinoma", "microwave ablation", "radio-frequency ablation", and "laser ablation", among others, were comprehensively reviewed in this article. The follow-up outcomes of patients in these articles were analyzed.

Results

The efficacy and safety of TA including microwave ablation (MWA), laser ablation (LA), and radiofrequency ablation (RFA) in the treatment of PTC and PTC have been intensively studied. Based on existing clinical trials, the relatively long-term follow-up (range, from 6 to 64.2 months) results in MWA, LA, and RFA were satisfactory that tumor volume reduction rate (VRR) reached and even surpass 99%. Compared with routine surgery methods (total thyroidectomy and lobectomy), the incidence rate of complications was relatively lower and the recurrence rate of TA techniques was not statistically significant, whereas the operative time, blood loss, length of hospital stay, and hospital cost were significantly decreased.

Conclusion

TA presents the same satisfactory therapeutic effects but minimal postoperative trauma can significantly improve the patients' quality of life. However, future larger sample, multicenter, and prospective randomized controlled trials are urgently needed to validate the feasibility of TA in dealing with PTMC.

Thermal Ablation Induces Transitory Metastatic Growth by Means of the STAT3/c-Met Molecular Pathway in an Intrahepatic Colorectal Cancer Mouse Model

Background Systemic protumorigenic effects have been noted after radiofrequency ablation (RFA) of normal liver and have been linked to an interleukin 6/signal transducer and activator of transcription 3 (STAT3)/hepatocyte growth factor (HGF)/tyrosine-protein kinase Met (c-Met)/vascular endothelial growth factor (VEGF) cytokinetic pathway. Purpose To elucidate kinetics of RFA protumorigenic effects on intrahepatic metastatic implantation and growth and determine potential molecular targets for pharmacologic suppression of these effects. Materials and Methods An intrahepatic metastasis model was established by implanting CT26 and MC38 tumor cells into 216 7-8-week-old male Balb/C and C57BL6 mice, respectively, by means of splenic injection. Between June 2017 and March 2019, mice underwent tumor injection, followed 24 hours later by either standardized RFA (70°C ± 1, 5 minutes, 1-cm tip) or a sham procedure (needle placement without heating) (12 animals per arm, n = 48). Next, RFA or sham procedures were performed, followed by splenic tumor cell injection at 1 day, 3 days, or 7 days later (six animals per arm, n = 72). Finally, PHA-665752 and S3I-201 were used to block c-Met or STAT3, respectively, prior to either RFA or sham treatment (six animals per arm, n = 96). Livers were harvested at 14 days for CT26 and 21days for MC38 for tumor quantification. Ki-67 and CD34 immunohistochemistry measured proliferative indexes and microvascular density, respectively. Data were compared with analysis of variance and the two-tailed Student t test. Results RFA performed after tumor cell injection induced increased metastatic tumor number (103 ± 45 vs 52 ± 44 [CT26], P = .009 and 87 ± 51 vs 39 ± 20 [MC38], P = .007), cellular proliferation (P < .001 for both), and intratumoral neovascularization (P < .001 for both), compared with the sham procedure. Tumor cell injection performed 1 day and 3 days after RFA also increased these indexes (P < .05), while no difference was demonstrated for cell injection 7 days after RFA (P > .05). Adjuvant c-Met or STAT3 inhibition reduced intrahepatic metastatic parameters after RFA to baseline (P < .03), equivalent to the sham group (P > .05). Conclusion Radiofrequency ablation of normal liver promotes intrahepatic metastatic implantation and increased growth over a short-lived (1-3 days) temporal window in animal models. This phenomenon can be potentially neutralized with specific inhibition of pathways including hepatocyte growth factor/tyrosine-protein kinase Met and signal transducer and activator of transcription 3. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Nikolic in this issue.

Single-Dose Neoadjuvant AKT Pathway Inhibitor Reduces Growth of Hepatocellular Carcinoma after Laser Thermal Ablation in Small-Animal Model

BackgroundLocal recurrence following thermal ablation of hepatocellular carcinoma (HCC) larger than 2-3 cm remains a challenging clinical problem. Prior studies suggest that phosphoinositide 3-kinase (PI3K)/mammalian target of rapamycin (mTOR)-dependent protein kinase B (AKT) signaling mediates HCC cell survival caused by moderate heat stress in vitro, but these findings need in vivo validation.PurposeTo test the hypothesis that neoadjuvant inhibition of PI3K/mTOR/AKT signaling reduces HCC tumor growth in vivo after laser ablation and to evaluate the effects of moderate heat stress on molecular signaling and cellular function in HCC cells in vitro.Materials and MethodsHCC tumor-bearing mice were randomized to neoadjuvant PI3K/mTOR inhibitor (BEZ235) or control groups followed by an intentional partial laser ablation or sham ablation; there were at least nine mice per group. Postablation tumor growth was monitored up to 7 days. Tumor volumes were compared for drug or ablation groups by using two-way analysis of variance. N1S1 HCC cells pretreated with BEZ235 or control and subjected to moderate heat stress (45°C for 10 minutes) or control (37°C for 10 minutes) were analyzed by using mass spectrometry. Protein interaction networks were derived from protein expression analysis software, and cellular function activation state (Z-score) and fold-change in AKT phosphorylation were calculated.ResultsThere was a 37%-75% reduction in HCC tumor volume by day 7 after ablation in the BEZ235 plus ablation group (713 mm3 ± 417) compared with vehicle plus sham (1559 mm3 ± 552), vehicle plus ablation (1041 mm3 ± 591), and BEZ235 plus sham (1108 mm3 ± 523) groups (P < .001, P = .04, and P = .005, respectively). PI3K/mTOR inhibition prevented moderate heat stress-induced AKT signaling (Z-score, -0.2; P < .001) and isoform-specific AKT phosphorylation compared with the vehicle plus heat stress group. PI3K/mTOR inhibition prevented moderate heat stress-induced global effects on HCC molecular signaling and cellular function, including decreased cell survival, growth, and proliferation (Z-score, -0.3 to -3.2; P < .001) and increased apoptosis and cell death (Z-score, 0.4-1.1; P < .001).ConclusionModerate heat stress induces PI3K/mTOR/AKT-dependent global effects on hepatocellular carcinoma (HCC) cell survival, function, and death. Neoadjuvant PI3K/mTOR/AKT inhibition reduces postablation HCC tumor growth.© RSNA, 2019Online supplemental material is available for this article.See also the editorial by White in this issue.

PKI-587 enhances chemosensitivity of oxaliplatin in hepatocellular carcinoma through suppressing DNA damage repair pathway (NHEJ and HR) and PI3K/AKT/mTOR pathway

Oxaliplatin resistance limits its effectiveness in the treatment of hepatocellular carcinoma (HCC). Abnormal activation of the PI3K/AKT/mTOR pathway has been associated with decreased survival of HCC patients, anti-apoptosis after chemotherapeutic drug-induced DNA damage, and chemoresistance. In this research, we evaluated the effect of the dual PI3K/mTOR inhibitor, PKI-587, on the sensitivity of oxaliplatin in HCC. Two HCC cell lines (HepG2 and SK-Hep1) were used to analyze PKI-587 for DNA damage response, cell proliferation, clonogenic survival, cell cycle and apoptosis after oxaliplatin treatment. A HepG2 tumor-bearing model was used to assess the in vivo effects of the combination of the two compounds. In HCC cells, oxaliplatin stably activated the PI3K/AKT/mTOR pathway, including up-regulation of p-Akt (Ser473), p-mTOR (Ser2448), p-mTOR (Ser2481), p-elF4EBP1, and p-S6K1, and activated the DNA damage repair pathways (non-homologous end joining (NHEJ) and homologous recombination (HR)), up-regulation of p-DNAPKcs (Ser2056), p-ATM (Ser1981), and p-ATR (Ser428), which were attenuated by PKI-587. Compared with oxaliplatin alone, the combination of PKI-587 and oxaliplatin increased the number of γ-H2AX/cells, decreased proliferation of cells, and an increased the percentage of G0/G1 phase cells and apoptotic cells. In vivo, the combination of oxaliplatin with PKI-587 inhibited tumor growth. Anti-tumor effects were associated with induction of mitochondrial apoptosis and inhibition of phosphorylation of mTOR, Akt and γ-H2AX. We conclude that PKI-587 enhances chemosensitivity of oxaliplatin in HCC through suppressing the PI3K/AKT/mTOR signalling pathway and inhibiting the DNA damage repair pathway. The combination of PKI-587 and oxaliplatin appears to be a promising regimen for the treatment of HCC.

Prediction of Gold Nanoparticle and Microwave-Induced Hyperthermia Effects on Tumor Control via a Simulation Approach

Hyperthermia acts as a powerful adjuvant to radiation therapy and chemotherapy. Recent advances show that gold nanoparticles (Au-NPs) can mediate highly localized thermal effects upon interaction with laser radiation. The purpose of the present study was to investigate via in silico simulations the mechanisms of Au-NPs and microwave-induced hyperthermia, in correlation to predictions of tumor control (biological endpoints: tumor shrinkage and cell death) after hyperthermia treatment. We also study in detail the dependence of the size, shape and structure of the gold nanoparticles on their absorption efficiency, and provide general guidelines on how one could modify the absorption spectrum of the nanoparticles in order to meet the needs of specific applications. We calculated the hyperthermia effect using two types of Au-NPs and two types of spherical tumors (prostate and melanoma) with a radius of 3 mm. The plasmon peak for the 30 nm Si-core Au-coated NPs and the 20 nm Au-NPs was found at 590 nm and 540 nm, respectively. Considering the plasmon peaks and the distribution of NPs in the tumor tissue, the induced thermal profile was estimated for different intervals of time. Predictions of hyperthermic cell death were performed by adopting a three-state mathematical model, where “three-state” includes (i) alive, (ii) vulnerable, and (iii) dead states of the cell, and it was coupled with a tumor growth model. Our proposed methodology and preliminary results could be considered as a proof-of-principle for the significance of simulating accurately the hyperthermia-based tumor control involving the immune system. We also propose a method for the optimization of treatment by overcoming thermoresistance by biological means and specifically through the targeting of the heat shock protein 90 (HSP90), which plays a critical role in the thermotolerance of cells and tissues.

Heat Stress and Thermal Ablation Induce Local Expression of Nerve Growth Factor Inducible (VGF) in Hepatocytes and Hepatocellular Carcinoma: Preclinical and Clinical Studies

The purposes of this study were to test the hypothesis that heat stress and hepatic thermal ablation induce nerve growth factor inducible (VGF) and to determine intrahepatic versus systemic VGF expression induced by thermal ablation in vivo and in patients. Hepatocytes and HCC cells were subjected to moderate (45°C) or physiologic (37°C) heat stress for 10 min and assessed for VGF expression at 0-72 h post-heat stress (n ≥ 3 experiments). Orthotopic N1S1 HCC-bearing rats were randomized to sham or laser thermal ablation (3 W × 90 s), and liver/serum was harvested at 0-7 days postablation for analysis of VGF expression (n ≥ 6 per group). Serum was collected from patients undergoing thermal ablation for HCC (n = 16) at baseline, 3-6, and 18-24 h postablation and analyzed for VGF expression. Data were analyzed using ordinary or repeated-measures one-way analysis of variance and post hoc pairwise comparison with Dunnett's test. Moderate heat stress induced time-dependent VGF mRNA (3- to 15-fold; p < 0.04) and protein expression and secretion (3.1- to 3.3-fold; p < 0.05). Thermal ablation induced VGF expression at the hepatic ablation margin at 1 and 3 days postablation but not remote from the ablation zone or distant intrahepatic lobe. There was no detectable serum VGF following hepatic thermal ablation in rats and no increase in serum VGF following HCC thermal ablation in patients at 3-6 and 18-24 h postablation compared to baseline (0.71- and 0.63-fold; p = 0.27 and p = 0.16, respectively). Moderate heat stress induces expression and secretion of VGF in HCC cells and hepatocytes in vitro, and thermal ablation induces local intrahepatic but not distant intrahepatic or systemic VGF expression in vivo.

JTC-801 inhibits the proliferation and metastasis of the Hep G2 hepatoblastoma cell line by regulating the phosphatidylinositol 3-kinase/protein kinase B signalling pathway

The increased worldwide mortality rate due to liver cancer may be attributed to the aggressive nature of the disease. Signal transduction through G-protein-coupled receptors (GPCRs) can affect a number of aspects of cancer biology, including invasion, migration and vascular remodelling. JTC-801, a novel GPCR antagonist, has demonstrated promising anticancer effects in adenocarcinoma and osteosarcoma cells. In the present study, the effect of JTC-801 on the proliferation and migration of hepatoblastoma Hep G2 cells was investigated. The Cell Counting Kit-8 assay revealed that JTC-801 markedly suppressed the growth of the Hep G2 cells. Additionally, JTC-801 significantly inhibited cell invasion and migration in a Transwell assay. Furthermore, the expression of anti-apoptotic protein B-cell lymphoma 2 decreased and the expression of the pro-apoptotic proteins active caspase-3 and apoptosis regulator BAX increased in the Hep G2 cells following JTC-801 treatment. Additionally, JTC-801 suppressed the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signalling pathway in the Hep G2 cells. Therefore, the present study revealed that JTC-801 can induce the apoptosis of Hep G2 cells by regulating the PI3K/AKT signalling pathway, which suggests that JTC-801 may be a potential novel drug target for clinical liver cancer treatment.