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

Abstract

PurposeRadiofrequency ablation (RFA) therapy has proven to be effective and feasible for early-stage hepatocellular carcinoma (HCC); however, rapid progression of residual tumor cells after RFA has been confirmed, but the molecular mechanisms of this phenomenon are poorly understood. This study evaluated the effect of the lipid raft proteins known as flotillins on the invasive and metastatic potential of residual HCC.MethodsThe human HCC cell line HCCLM3 was used to establish insufficient RFA models in vivo and in vitro. Changes in cellular morphology, soft agar colony formation, motility, metastasis, and epithelial–mesenchymal transition (EMT) markers after insufficient RFA intervention in vitro and in vivo were detected by real-time PCR, western blotting, immunohistochemistry and transwell assays.ResultsThe results showed that flotillin-1 and flotillin-2 expression were upregulated in HCCLM3 cells following 45 °C heat treatment and in residual HCCLM3 xenografts cells after insufficient RFA. Knocking down flotillin-1 or flotillin-2 in HCCLM3 cells by shRNA significantly lowered insufficient RFA-induced tumor growth, EMT changes, and metastasis in vitro and in vivo. Furthermore, mechanism studies indicated that flotillins altered the EMT status and metastatic potential of heat-treated HCCLM3 cells by activating the Akt/Wnt/β-catenin signaling pathway.ConclusionsOur findings present new evidence that flotillins play a key role in the aggressive behaviors of residual cancer cells after insufficient RFA and provide new insights into the regulatory mechanism of Wnt/β-catenin signaling.Electronic supplementary materialThe online version of this article (10.1007/s00432-019-02852-z) contains supplementary material, which is available to authorized users.

Flotillin membrane domains in cancer

“…Moreover, in condition of suboptimal cancer treatment, metastasis formation is enhanced, as reported for small-size hepatocellular carcinoma with insufficient radiofrequency ablation. When hepatocellular carcinoma cells are heat-treated to mimic this process, flotillin upregulation is observed [67].…”

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

“…Unfortunately, in the case of multinodular or large HCC lesions, the initial CR sharply drops to almost 50% [18]. Insu cient RFA would possibly promote the proliferation of residual HCCs [34], accelerate metastasis in a variety of ways [35], and further contribute to a lower OS rate in patients with HCCs treated by RFA [36]. Because RFA does not remove the corresponding hepatic segment fed by the tumor-bearing portal tributaries [37], arterioportal stula and intratumoral shunt develop, intratumoral pressure suddenly increases during RFA treatment, resulting in the intravascular spread of tumor cells [36].…”

Comparison open liver resection and RFA on the treatment of solitary 3-5cm hepatocellular carcinoma

“…However, due to the limitations of the background of liver and the liver function situation, postoperative complications also need to be taken into account. RFA surgery is the relatively safe treatment approach, but the stability and thoroughness for RFA to treat liver cancer are difficult to determine [10,11]. Although the evaluation of effectiveness between the two approaches is still in debate, in Western countries, especially in the United States, the treatment guidelines on liver cancer consistently require surgical resection for early liver cancer if the liver function allows and if there is no high vein pressure [12].…”