Factors associated with increased risk of peritoneal seeding after radiofrequency ablation for hepatocellular carcinoma

PURPOSE

To evaluate the incidence, risk factors, and prognosis associated with peritoneal seeding after percutaneous radiofrequency ablation (RFA) for HCC, focusing on viable tumors after previous locoregional treatment, including TACE and RFA.

METHODS

Exactly 290 patients (mean age, 67.9 years ± 9.74; 223 men) with 383 HCCs (mean size, 15.9 mm ± 5.49) who underwent RFA between June 2012 and December 2019 were included in this retrospective study. Among them, 158 had history of previous treatment (mean number, 1.3 ± 1.8) with 109 viable HCCs. Cumulative seeding after RFA was estimated using the Kaplan-Meier method. Independent factors affecting seeding were investigated using multivariable Cox proportional hazards regression analysis.

RESULTS

Median follow-up was 1175 days (range: 28-4116). Seeding incidence was 4.1 (12/290) and 4.7% (17/383) per patient and tumor, respectively. The median time interval between RFA and detection of seeding was 785 days (range: 81-1961). Independent risk factors for seeding included subcapsular tumor location (hazard ratio [HR] 4.2; 95% confidence interval [CI] 1.4, 13.0; p = 0.012) and RFA for viable HCC after previous locoregional treatment (HR 4.5; 95% CI 1.7, 12.3; p = 0.003). Subgroup analysis for viable tumors, revealed no significant difference in cumulative seeding rates between the TACE and RFA groups (p = 0.078). Cumulative overall survival rates differed significantly between patients with and without seeding metastases (p < 0.001).

CONCLUSION

Peritoneal seeding after RFA is a rare, delayed complication. Subcapsular-located and viable HCC after previous locoregional treatment are potential risk factors for seeding. Seeding metastases could affect the prognosis of patients who cannot receive local therapy.

Mitotic quiescence in hepatic cancer stem cells: An incognito mode

Hepatocellular carcinoma represents one of the most aggressive cancers with high recurrence rates. The high recurrence is a major problem in the management of this disease. Cancer stem cells (CSCs) are often regarded as the basis of cancer recurrence. The anti-proliferative therapy kills the proliferating cells but induces mitotic quiescence in CSCs which remain as residual dormant CSCs. Later on, withdrawal of treatment reactivates the residual CSCs from dormancy to produce new cancer cells. The proliferation of these newly formed cancer cells initiates new tumor formation in the liver leading to tumor recurrence. HCC cells evade the immune surveillance via modulating the key immune cells by alpha feto-protein (AFP) secreted from CSCs or hepatic progenitor cells. This AFP mediated immune evasion assists in establishing new tumors by cancer cells in the liver. In this review, we will summarise the CSC mechanisms of recurrence, mitotic quiescence, dormancy and reactivation of CSCs, metastasis and immune evasion of hepatocellular carcinoma.

Expressions of hypoxia-inducible factor-1 and epithelial cell adhesion molecule are linked with aggressive local recurrence of hepatocellular carcinoma after radiofrequency ablation therapy

BACKGROUND

Radiofrequency ablation (RFA) is a widely used therapy for hepatocellular carcinoma (HCC). Several reports have demonstrated the aggressive local recurrence of HCC after RFA, suggesting that induction of further malignant transformation of HCC has occurred.

METHODS

Eighty-eight (88) patients with HCC who underwent hepatic resection were included in this study. Hepatectomy was indicated for local recurrence of HCC after RFA (n = 10, RFA group) and for HCC without prior RFA (n = 78, non-RFA group). Clinicopathological data and the patient's prognosis after hepatectomy were compared between the two groups. Expression levels of hypoxia-inducible factor-1 (HIF-1), epithelial cell adhesion molecule (EpCAM), CD44, and vascular endothelial growth factor messenger RNA (mRNA) in the tumor tissues were also examined.

RESULTS

The RFA group showed higher frequency of portal vein invasion and less tumor differentiation compared with the non-RFA group (p < 0.05). Overall and disease-free survival rates in the RFA group were significantly worse than those in the non-RFA group (p < 0.05). HIF-1 and EpCAM mRNA expression levels in the RFA group were significantly higher than those in the non-RFA group (p < 0.05).

CONCLUSIONS

These results suggest that local HCC recurrence after RFA shows an aggressive tumor phenotype and poor prognosis through the enhanced expressions of HIF-1 and EpCAM in the residual HCC tumors after insufficient or sub-lethal treatment by RFA.

Radiofrequency ablation induces dedifferentiation of hepatocellular carcinoma

Radiofrequency ablation (RFA) has been reported to be a minimally invasive and effective procedure for the treatment of hepatocellular carcinoma (HCC). However, the pattern of recurrence and complications following RFA have yet to be fully identified. During the period January 2000 to December 2006, we performed HCC resections in 15 patients who developed local recurrence after RFA, as well as in 144 patients without RFA. In patients with local recurrence of HCC after RFA, the tumors showed a more invasive growth, more vascular invasion and less differentiation compared with tumors of patients without RFA. In 6 of the 15 patients with recurrence after RFA, needle biopsy of the HCC was performed before tumor ablation. In five of these 6 patients, dedifferentiation of the tumor was observed. These findings suggest that heat shock due to RFA induces dedifferentiation of HCC. Recurrence after RFA may result in an aggressive tumor that precludes any possibility of cure. RFA must not be considered a suitable alternative to surgery in patients with a low surgical risk. Instead, RFA should be performed according to strict indications by skilled operators using the latest devices.

Glycogen synthase kinase 3: an emerging therapeutic target

Glycogen synthase kinase 3 (GSK-3) is a serine/threonine protein kinase that has recently emerged as a key target in drug discovery. It has been implicated in multiple cellular processes and linked with the pathogenesis of several diseases. GSK-3 inhibitors might prove useful as therapeutic compounds in the treatment of conditions associated with elevated levels of enzyme activity, such as type 2 diabetes and Alzheimer's disease. The pro-apoptotic feature of GSK-3 activity suggests a potential role for its inhibitors in protection against neuronal cell death, and in the treatment of traumatic head injury and stroke. Finally, selective inhibitors of GSK-3 could mimic the action of mood stabilizers such as lithium and valproic acid and be used in the treatment of bipolar mood disorders.

Molecular cloning and expression analysis of human glycogen synthase kinase-3 alpha promoter

Human glycogen synthase kinase-3 alpha (GSK-3 alpha) is a serine/threonine kinase that phosphorylates a variety of cytoplasmic and nuclear proteins. It also phosphorylates components of the neuronal cytoskeleton including tau and neurofilament heavy chain. Hyperphosphorylated tau is found in neurofibrillary tangles, a hallmark of Alzheimer's disease and aberrant phosphorylation of neurofilament heavy chain is observed in motor neuron disease. Alterations in GSK-3 alpha activity may therefore contribute to the disease process in these disorders. As a first step to understand the transcriptional regulation of GSK-3 alpha, a 2-kb (p-1751/+243) DNA fragment upstream of the GSK-3 alpha initiation codon was obtained from a YAC clone and characterised. Using primer extension assays, a putative transcriptional start site was located to a G nucleotide 244 bp upstream of the ATG codon. Several transcription factor-binding sites were identified on the promoter region, but no TATA-like element was located close to the start site. Deletion mutants of the 2-kb DNA fragment were generated and fused to a promoterless chloramphenicol acetyltransferase (CAT) gene. Transfection study in a neuroblastoma cell line revealed the 1-kb (p-719/+243) fragment carried strong promoter activity, while the 2-kb construct that contains an Alu-like sequence was only 50% active.

Molecular cloning and characterization of the human glycogen synthase kinase-3beta promoter

Glycogen synthase kinase 3beta (GSK-3beta) is a proline-directed kinase that forms part of the wingless signaling pathway. Recent studies have shown that GSK-3beta phosphorylates the microtubule-associated protein tau in vitro and in cell culture. Tau is the principal component of the paired helical filaments (PHFs) found in the brains of patients with Alzheimer disease, and PHF-tau is hyperphosphorylated. GSK-3beta is therefore one of the candidate kinases for phosphorylating tau in Alzheimer disease. GSK-3beta activity is negatively regulated by phosphorylation on serine 9 and positively regulated by phosphorylation on tyrosine 216. However, since overexpression of GSK-3beta by transfection leads to increased activity in the absence of any stimuli, GSK-3beta activity may also be regulated at the transcriptional level. Indeed, increased GSK-3beta protein levels are found in Alzheimer disease brains, and GSK-3beta is found associated with PHFs in Alzheimer disease. To understand how GSK-3beta activity may be regulated at the transcriptional level, we have isolated the human GSK-3beta promoter. The GSK-3beta promoter does not contain a conventional TATA box although several other transcription factor binding sites were identified. A putative transcription start site was mapped by 5' RACE. Transfection of various GSK-3beta promoter CAT reporter genes into both COS-7 cells and SHSY5Y neuronal cells revealed that the GSK-3beta promoter is more active in neuronal cells. Such transfection studies involving promoter deletion mutants revealed that a negative transcriptional response element may be present at position -1421 to -1363 and an activator sequence at position -427 to -384. CP2 binding sites were also present within the promoter. CP2 has recently been shown to interact with the Alzheimer disease amyloid precursor protein binding protein Fe65. The significance of these results with respect to Alzheimer disease pathogenesis are discussed.

Glycogen synthase kinase 3beta and extracellular signal-regulated kinase inactivate heat shock transcription factor 1 by facilitating the disappearance of transcriptionally active granules after heat shock

Heat shock transcription factor 1 (HSF-1) activates the transcription of heat shock genes in eukaryotes. Under normal physiological growth conditions, HSF-1 is a monomer. Its transcriptional activity is repressed by constitutive phosphorylation. Upon activation, HSF-1 forms trimers, acquires DNA binding activity, increases transcriptional activity, and appears as punctate granules in the nucleus. In this study, using bromouridine incorporation and confocal laser microscopy, we demonstrated that newly synthesized pre-mRNAs colocalize to the HSF-1 punctate granules after heat shock, suggesting that these granules are sites of transcription. We further present evidence that glycogen synthase kinase 3beta (GSK-3beta) and extracellular signal-regulated kinase mitogen-activated protein kinase (ERK MAPK) participate in the down regulation of HSF-1 transcriptional activity. Transient increases in the expression of GSK-3beta facilitate the disappearance of HSF-1 punctate granules and reduce hsp-70 transcription after heat shock. We have also shown that ERK is the priming kinase for GSK-3beta. Taken together, these results indicate that GSK-3beta and ERK MAPK facilitate the inactivation of activated HSF-1 after heat shock by dispersing HSF-1 from the sites of transcription.