Heat shock protein 70 expression and effect of combined transcatheter arterial embolization and radiofrequency ablation in the rabbit VX2 liver tumour model

HSP70 via HIF-1 α SUMOylation inhibits ferroptosis inducing lung cancer recurrence after insufficient radiofrequency ablation

Radiofrequency ablation (RFA) is an effective and feasible therapy for lung cancer, but accelerated progression of residual non-small cell lung cancer (NSCLC) after incomplete radiofrequency ablation (RFA) has frequently been reported. A previous study reported that HSP70 and HIF-1α were highly expressed in areas with incomplete RFA. Therefore, we sought to elucidate the regulatory effect of the HIF-1α/HSP70 pathway on lung cancer recurrence after incomplete radiofrequency ablation. In this study, we found that knockdown of HSP70 can reduce sumo 1, sumo 2/3 (marker of SUMOylation) of HIF-1α and inhibit A549 cell proliferation and migration under heat stress conditions (used to simulate incomplete RFA in vitro). We observed that knockdown of HSP70 altered the expression of ferroptosis-related proteins and genes (SLC7A11 and ACSL3), and the RNA-seq results showed that knockdown of HSP70 activated the ferroptosis pathway, further confirming that HSP70 regulates ferroptosis. In summary, HSP70, via HIF-1α SUMOylation, inhibited ferroptosis, inducing lung cancer recurrence after radiofrequency ablation. The study reveals a new direction for further research on therapeutic targets to suppress lung cancer recurrence and provides a theoretical foundation for further clinical studies.

Liposome quercetin enhances the ablation effects of microwave ablation in treating the rabbit VX2 liver tumor model

OBJECTIVE

This study aimed to investigate whether liposomal quercetin (LQ) could enhance the effects of microwave ablation (MVA) in treating the rabbit VX2 liver tumor model.

METHODS

Rabbits with VX2 liver tumors were randomly divided into three groups: intravenous LQ group (LQ group), MWA group and LQ combined with MWA (LQ + MWA) group. Five rabbits were randomly selected and sacrificed from each group at 12 h and on days 3, 7 and 14 of the operation. The tumor samples were detected and quantified by immunohistochemistry, Western blot, and reverse transcription polymerase chain reaction (RT-PCR).

RESULTS

For up to 7 days, the coagulation necrosis volume (CV) of the LQ + MWA group was larger than that of MWA and LQ groups (p < 0.05). Fourteen days after the operation, the total tumor volume of the LQ + MWA group was smaller than that of the LQ group and the MWA group (p < 0.05). The survival time of the LQ + MWA group was significantly longer than that of the MWA and LQ groups (p < 0.01). Heat shock protein 70 (HSP70), hypoxia inducible factor-1 α (HIF-1 α), vascular endothelial growth factor (VEGF), tumor microvessel density (MVD) were lower in the LQ + MWA group than the MWA and LQ groups at 12 h, on days 3 and 7. At hour 12 and on days 3 and 7, HSP70 mRNA and HIF-1α mRNA expression of MWA group were significantly higher than that of the LQ and LQ + MWA groups (p < 0.001). At 12 h, and on days 3 and 7, apoptotic rate of tumor cells in LQ + MWA group was higher than that of the MWA and LQ groups (p < 0.05). At 12 h and on days 3, 7 and 14, the proliferation index of tumor cells in residual tumor in LQ + MWA group was lower than that in the MWA and LQ groups (p < 0.05).

CONCLUSION

Preoperative infusion of LQ can significantly enhance the MWA effects of liver VX2 tumor, inhibit the excessive proliferation of residual tumor and angiogenesis, and decrease metastasis and prolong the survival period of experimental animals.

Hypoxia-Induced Cancer Cell Responses Driving Radioresistance of Hypoxic Tumors: Approaches to Targeting and Radiosensitizing

Simple Summary

Some regions of aggressive malignancies experience hypoxia due to inadequate blood supply. Cancer cells adapting to hypoxic conditions somehow become more resistant to radiation exposure and this decreases the efficacy of radiotherapy toward hypoxic tumors. The present review article helps clarify two intriguing points: why hypoxia-adapted cancer cells turn out radioresistant and how they can be rendered more radiosensitive. The critical molecular targets associated with intratumoral hypoxia and various approaches are here discussed which may be used for sensitizing hypoxic tumors to radiotherapy.

Abstract

Within aggressive malignancies, there usually are the “hypoxic zones”—poorly vascularized regions where tumor cells undergo oxygen deficiency through inadequate blood supply. Besides, hypoxia may arise in tumors as a result of antiangiogenic therapy or transarterial embolization. Adapting to hypoxia, tumor cells acquire a hypoxia-resistant phenotype with the characteristic alterations in signaling, gene expression and metabolism. Both the lack of oxygen by itself and the hypoxia-responsive phenotypic modulations render tumor cells more radioresistant, so that hypoxic tumors are a serious challenge for radiotherapy. An understanding of causes of the radioresistance of hypoxic tumors would help to develop novel ways for overcoming this challenge. Molecular targets for and various approaches to radiosensitizing hypoxic tumors are considered in the present review. It is here analyzed how the hypoxia-induced cellular responses involving hypoxia-inducible factor-1, heat shock transcription factor 1, heat shock proteins, glucose-regulated proteins, epigenetic regulators, autophagy, energy metabolism reprogramming, epithelial–mesenchymal transition and exosome generation contribute to the radioresistance of hypoxic tumors or may be inhibited for attenuating this radioresistance. The pretreatments with a multitarget inhibition of the cancer cell adaptation to hypoxia seem to be a promising approach to sensitizing hypoxic carcinomas, gliomas, lymphomas, sarcomas to radiotherapy and, also, liver tumors to radioembolization.

Impact of Interventional Oncology Therapies on Tumor Microenvironment and Strategies to Enhance Their Efficacy

OBJECTIVE

We provide a brief review of the tumor microenvironment, the impact of six interventional radiology treatments on the tumor microenvironment, and potential methods to improve treatment efficacy.

CONCLUSION

Interventional oncology plays a unique role in cancer therapy, contributing to both antitumorigenic and protumorigenic effects.

The influence of liposomal quercetin on liver damage induced by microwave ablation

This study aimed to observe whether liposomal quercetin (LQ) can enhance the effect of microwave ablation (MWA) on hepatic parenchyma destruction. Forty-eight rabbits were randomly divided into three groups: LQ group, MWA group and LQ + MWA group. Serum and liver samples were collected. The coagulation volume (CV) of hepatic parenchyma, histopathological changes and liver function were compared. Hepatocyte apoptosis was examined through TUNEL. The expression of heat shock protein 70 (HSP70), hypoxia-inducible factor-1α (HIF-1α) and tumor necrosis factor-α (TNF-α) were analyzed. Compared with MWA group, the CV of coagulation necrosis in liver was significantly increased in LQ + MWA group. TUNEL results showed that the hepaocyte apoptosis was higher in LQ + MWA group than MWA group on 12 h, 24 h and 3 d, respectively. HSP70 and HIF-1α expression in both MWA group and LQ + MWA group were increased at 12 and 24 hours, peaked on day3 and dropped on day7. Compared with MWA group, HSP70 and HIF-1α expression were lower in LQ + MWA group. On the contrary, TNF-α expression was decreased in MWA group and LQ + MWA group compared with LQ group. In conclusion, LQ increased hepatocyte apoptosis and MWA-induced hepatic parenchyma destruction through suppressing HSP70 and HIF-1α expression in liver surrounding ablation zone and increasing TNF-α expression.

Transcatheter arterial embolization combined with radiofrequency ablation activates CD8(+) T-cell infiltration surrounding residual tumors in the rabbit VX2 liver tumors

Purpose

To evaluate the effect of transcatheter arterial embolization (TAE) combined with radiofrequency ablation (RFA) treatment (TAE + RFA) on the expression of heat shock protein 70 (HSP70) in residual tumors and explore the relationship between the HSP70 and CD8⁺ T-cell infiltrate surrounding residual tumors in the rabbit VX2 liver tumor model.

Materials and methods

Animals with VX2 liver tumors were randomized into four groups (control, TAE, RFA, and TAE + RFA) with 15 rabbits in each group. Five rabbits in each group were sacrificed on days 1, 3, and 7 after treatment. HSP70 expression and infiltration of CD8⁺ T-cells in the liver and residual tumors surrounding the necrosis zone were detected by immunohistochemistry staining. The maximal diameters of tumor necrosis, numbers of metastases, and tumor growth rate were compared on day 7 after treatment.

Results

TAE + RFA achieved larger maximal diameter of tumor necrosis, lower tumor growth rate, and fewer metastatic lesions, compared with other treatments on day 7. The number of CD8⁺ T-cells in the TAE + RFA group was significantly higher than in other groups on days 1, 3, and 7. There was a positive correlation between HSP70 expression level and infiltration of CD8⁺ T-cells surrounding the residual tumor on day 1 (r=0.9782, P=0.012), day 3 (r=0.93, P=0.021), and day 7 (r=0.8934, P=0.034).

Conclusion

In the rabbit VX2 liver tumor model, TAE + RFA activated the highest number of CD8⁺ T-cells surrounding residual tumors. TAE + RFA appears to be a beneficial therapeutic modality for tumor control and antitumor immune response in this model.

Low-frequency and low-intensity ultrasound-mediated microvessel disruption enhance the effects of radiofrequency ablation on prostate cancer xenografts in nude mice

The aim of the present study was to examine the impact of low-frequency, low-intensity ultrasound (US)-stimulated microbubbles (USMB) on radiofrequency ablation (RFA) in the treatment of nude mice with human prostate cancer xenografts. The tumor‑bearing nude mice were divided into three groups: The USMB+RFA group was treated with USMB immediately followed by RFA, the RFA group was treated with RFA alone, and the control group remained untreated. The animals underwent enhanced US to calculate the tumor volumes, ablation volumes and ablation rates. Subsequently, the tumors were excised for hematoxylin and eosin staining, to identify necrosis in the tumors following the treatments, and immunohistochemical staining, to analyze the apoptotic index (AI), proliferative index (PI) and microvessel density (MVD) at 1, 4 and 7 days post-treatment. Each group contained five mice at each time‑point. Necrosis was apparent in the center of the tumors in the treatment groups. Ablation lesion volumes of the USMB+RFA group were larger than those in the RFA group at 1 and 4 days post‑treatment (P=0.002 and P=0.022, respectively), and the ablation rates of the USMB+RFA group were significantly higher, compared with the RFA group at the three time‑points (all P<0.001). There were fewer apoptotic cells and more proliferative cells in the RFA group, compared with the control group 1,4 and 7 days post‑treatment (all P<0.05). The AI of the USMB+RFA group was higher than that of the control group and lower than that of the RFA group 1 day post-treatment (P=0.034 and P=0.016, respectively). The PI of the USMB+RFA group was lower than that of the control group and higher than that of the RFA group 4 and 7 days post-treatment (all P<0.05). No significant differences were observed in MVD among the three groups throughout the experiment. In conclusion, exposure to USMB prior to RFA produced larger volumes of ablation, compared with treatment with RFA alone, and increased AI and reduced PI in the residual carcinoma cells induced by RFA.

Meta-analysis on radiofrequency ablation in combination with transarterial chemoembolization for the treatment of hepatocellular carcinoma

To evaluate the efficacy and safety of transcatheter arterial chemoembolization (TACE) combined with radiofrequency ablation (RFA) and TACE alone for hepatocellular carcinoma (HCC), Pubmed, Cochrane Library, Web of Science, China National Knowledge Infrastructure (CNKI) and Wanfang Datebases were searched for the randomized controlled trials (RCTs) and retrospective cohort studies from the establishment of the databases to January 2014. The bibliographies of the included studies were searched, too. After study selection, assessment, data collection and analysis were undertaken, we performed this meta-analysis by using the RevMan5.2 software. Seventeen studies involving 1116 patients met the inclusion criteria with 530 treated with RFA-plus-TACE and 586 with TACE alone. The results of meta-analysis showed that the combination of TACE and RFA was obviously associated with higher 1-, 2-, and 3-year overall survival rates (OR1-year=3.98, 95% CI 2.87-5.51, P<0.00001; OR2-year=3.03, 95% CI 2.10-4.38, P<0.00001; OR3-year=7.02, 95% CI 4.14-11.92, P<0.00001) than TACE alone. The tumor complete necrosis rate in patients treated with TACE and RFA was higher than that of TACE alone (OR=13.86, 95% CI 8.04-23.89, P<0.00001). And there was a significant difference in local recurrence rate between two different kinds of treatment (OR=0.24, 95%CI 0.14-0.44, P<0.00001). Additionally, combination of TACE and RFA was associated with higher complete tumor necrosis rates than TACE mono-therapy in the treatment of HCC. However, RFA plus TACE was found to be associated with a lower local recurrence rate than TACE monotherapy. TACE-plus-RFA treatment was associated with a higher response rate (RR) than the TACE-alone treatment (OR=3.90, 95% CI=2.37-6.42, P<0.00001). TACE-plus-RFA treatment did not differ from the TACE-alone treatment in terms of stable disease (SD) rate (OR=0.38, 95% CI=0.11-1.26, P=0.11). Meta-analyses showed that the combination of RFA and TACE was associated with a significantly lower progressive disease (PD) rate (OR=0.15, 95% CI=0.05-0.43, P=0.0005). The rate of AFP reducing or returning to normal in serum in RFA plus TACE group was obviously lower than TACE alone group (OR=4.62, 95% CI 2.56-8.34, P<0.00001). The effect of TACE plus RFA for HCC is better than TACE mono-therapy. The combined therapy can elevate the patients' overall survival rate, tumor necrosis rate and the rate of AFP reducing or returning to normal in serum and decrease local recurrence rate, PD rate compared with TACE alone.