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RNA-dependent protein kinase (PKR) may have a positive regulatory role in controlling tumor growth and progression in hepatocellular carcinoma (HCC). However, the downstream substrates and the molecular mechanism of PKR in the growth and progression of HCC have not been clarified. In this study, mass spectrometry analysis was performed with immunoprecipitated samples, and 4.1R was identified as a protein that binds to PKR. In transfected COS7 cells, an immunoprecipitation experiment showed that 4.1R binds to wild-type PKR, but not to a kinase-deficient mutant PKR, suggesting that PKR binds to 4.1R in a kinase activity-dependent manner. In HCC cell lines, HuH7 and HepG2, the expression level of 4.1R protein was shown to be regulated by protein expression and activation of PKR. Interestingly, high expression of 4.1R, as well as PKR, is associated with a worse prognosis in HCC. PKR increased HCC cell growth in both anchorage-dependent and anchorage-independent manners, whereas 4.1R was involved in HCC cell growth only in an anchorage-independent manner, not in an anchorage-dependent manner. The rescue experiment indicated that increased anchorage-independent growth of HCC cells by PKR might be caused by 4.1R. In conclusion, PKR associates with 4.1R and promotes anchorage-independent growth of HCC. The PKR-4.1R axis might be a new therapeutic target in HCC., Competing Interests: Declarations Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

A 79-year-old man received treatment for multiple intrahepatic hepatocellular carcinoma with atezolizumab + bevacizumab. However, he developed lower back pain attributed to spinal metastases upon tumor enlargement; thus, he was admitted to our hospital for a change from atezolizumab + bevacizumab to lenvatinib and radiation therapy for the spinal metastases. On the 11th day after starting lenvatinib treatment, a pulsatile aneurysm appeared in the tumor, detected using abdominal ultrasonography Micro B-flow imaging, which visualized blood flow at a high frame rate; this was diagnosed as a pseudoaneurysm. The patient refused treatment for the pseudoaneurysm; therefore, he was carefully followed up. Fortunately, the pseudoaneurysm disappeared on the 17th day. One month later, the tumor had become completely necrotic. Lenvatinib demonstrated effectiveness in inhibiting angiogenesis in the tumor, as evidenced by a decrease in tumor blood flow. This case report suggests that pseudoaneurysm formation within the tumor occurs early after the administration of lenvatinib; thus, clinicians must be aware of the potential risk of pseudoaneurysm rupture., (© 2024. Japanese Society of Gastroenterology.)

We herein report a 63-year-old man who presented with left lower jaw pain and was diagnosed with hepatocellular carcinoma with bone metastases post-examination. All tumors grew after immunotherapy with atezolizumab and bevacizumab, and his jaw pain worsened. After palliative radiation therapy, however, the tumors shrank markedly, with no recurrence seen after stopping immunotherapy. To our knowledge, this is the first case in which a radiotherapy- and immunotherapy-mediated abscopal effect facilitated tumor shrinkage and immunotherapy discontinuation.

The time point of the most precise predictor of hepatocellular carcinoma (HCC) development after viral eradication with direct-acting antiviral (DAA) therapy is unclear. In this study we developed a scoring system that can accurately predict the occurrence of HCC using data from the optimal time point. A total of 1683 chronic hepatitis C patients without HCC who achieved sustained virological response (SVR) with DAA therapy were split into a training set (999 patients) and a validation set (684 patients). The most accurate predictive scoring system to estimate HCC incidence was developed using each of the factors at baseline, end of treatment, and SVR at 12 weeks (SVR12). Multivariate analysis identified diabetes, the fibrosis-4 (FIB-4) index, and the α-fetoprotein level as independent factors at SVR12 that contributed to HCC development. A prediction model was constructed with these factors that ranged from 0 to 6 points. No HCC was observed in the low-risk group. Five-year cumulative incidence rates of HCC were 1.9% in the intermediate-risk group and 15.3% in the high-risk group. The prediction model at SVR12 most accurately predicted HCC development compared with other time points. This simple scoring system combining factors at SVR12 can accurately evaluate HCC risk after DAA treatment., (© 2023. The Author(s).)

Background: An unexpected recurrence of hepatocellular carcinoma (HCC) sometimes occurs in patients with hepatitis C virus (HCV) after treatment with direct-acting antivirals (DAAs). However, the characteristics of patients with HCC recurrence may differ depending on time after DAA treatment. We aimed to identify risk factors related to HCC recurrence according to time after DAA treatment., Methods: Of 1663 patients with HCV treated with a DAA, 199 patients had a previous history of HCC. We defined HCC recurrence within 1 year after DAA treatment as 'early recurrence', and recurrence more than 1 year after as 'late recurrence'. The different risk factors between the early and late phases of HCC recurrence after the end of DAA therapy were investigated., Results: Ninety-seven patients experienced HCC recurrence during the study period. Incidences of recurrence were 29.8, 41.0, and 53.4% at 1, 2, and 3 years, respectively, after the end of DAA therapy. Multivariate analysis identified post-treatment α-fetoprotein (AFP) as an independent factor contributing to HCC recurrence in the early phase (hazard ratio, 1.056; 95% confidence interval, 1.026-1.087, p < 0.001) and post-treatment estimated glomerular filtration rate (eGFR) (hazard ratio, 0.98; 95% confidence interval, 0.96-0.99, p = 0.032) as a predictor of HCC recurrence in the late phase., Conclusion: Patients with higher post-treatment AFP in the early phase and those with lower post-treatment eGFR in the late phase had a high risk of HCC recurrence. The risk factors associated with HCC recurrence after DAA treatment were different between the early and late phases.

Endoplasmic reticulum (ER) stress plays an important role in hepatocyte degeneration, especially in patients with chronic liver injury. Protein kinase R-like endoplasmic reticulum kinase (PERK) is a key molecule in ER stress. PERK may contribute to apoptotic cell death in HCC, however the details of the mechanism are not clear. In this study, we identified PERK-associated molecules using transcriptome analysis. We modulated PERK expression using a plasmid, tunicamycin and siRNA against PERK, and then confirmed the target gene expression with real-time PCR and Northern blotting. We further analyzed the apoptotic function. Transcriptome analysis revealed that expression of the RNA component of mitochondrial RNA processing endoribonuclease (RMRP), which is a long noncoding RNA, was strongly correlated with the function of PERK. The expression of RMRP was correlated with the expression of PERK in experiments with the siRNA and PERK plasmid in both HCC cell lines and human HCC tissue. Furthermore, RMRP downregulation induced apoptotic cell death. RMRP is downregulated by PERK, which induces apoptosis in HCC. RMRP could be a new therapeutic target to regulate HCC in patients with chronic liver diseases associated with ER stress.

Background: The effects of direct-acting antivirals (DAAs) on survival and recurrence rates after curative hepatocellular carcinoma (HCC) treatment in patients with hepatitis C virus (HCV) infection remain controversial., Methods: This retrospective, multicenter study involved Child-Pugh class A patients within the Milan criteria who had a first diagnosis of HCC and survived 6 months or longer after undergoing hepatectomy or radiofrequency ablation (RFA). The DAA-treated group (DAA group) included 56 patients, and the DAA-untreated group (untreated group) included 261 patients. The study was conducted using the propensity score-matched (1:2) DAA group and untreated group, 56 and 112 patients, respectively., Results: The survival rate at 48 months in the DAA group and the untreated group was 91.0% and 68.7%, respectively, showing significantly better survival in the DAA group (HR: 0.33; 95% CI 0.13-0.84; p = 0.021). The recurrence rate at 48 months was 36.7% and 66.7%, respectively, showing a significantly lower recurrence rate in the DAA group (HR, 0.46; 95% CI 0.27-0.77; p = 0.003). The median albumin-bilirubin (ALBI) score at 3 years post-HCC treatment was - 2.84 in the DAA group and - 2.34 in the untreated group. The ALBI score showed a significant improvement from baseline to 3 years post-HCC treatment (p = 0.001), whereas that in the untreated group showed a significant decline (p = 0.040)., Conclusions: DAAs after HCC treatment prevents deterioration of hepatic functional reserve and significantly improves both recurrence and survival rates.

Sex differences in the predictors for hepatocellular carcinoma (HCC) development after direct-acting antiviral (DAA) therapy was investigated. DAA therapy was given to 1438 (663 male, 775 female) patients. Sex differences in the HCC development rate and the factors contributing to HCC development after DAA therapy were investigated. Male patients had a significantly higher cumulative HCC incidence (log-rank test, P =  .007). On multivariate analysis, the fibrosis-4 index (HR = 1.11; 95%CI, 1.042-1.202, P =  .002) and posttreatment α-fetoprotein (AFP) (HR = 1.11; 95%CI, 1.046-1.197, P  =  .001) were found to be independent factors that contributed to HCC development following DAA therapy in female patients, whereas only posttreatment AFP (HR  =  1.090; 95%CI, 1.024-1.160, P  = .007) was an independent factor in male patients. The optimal posttreatment AFP cut-off values were set based on receiver operating characteristic curve analyses. The optimal posttreatment AFP cut-off value was much higher in females (6.0 ng/mL) than in male (3.5 ng/mL) patients. In conclusion both in male and female patients, posttreatment AFP was an independent predictor of HCC development after DAA therapy. However, the cut-off values differed between the sexes. In male patients, HCC could be seen in patients with relatively low posttreatment AFP levels; more careful observation might be needed in such patients., (© 2020 Wiley Periodicals LLC.)

The therapeutic effects of C16, which is an inhibitor of RNA-dependent protein kinase (PKR), on growth of hepatocellular carcinoma (HCC) cells and tumor progression in vitro and in vivo were evaluated. Huh7 cells, a human HCC cell line, were used. The effects of C16 on cell viability were evaluated with the MTT assay, and real-time RT-PCR was performed. Huh7 cells were grafted into immunodeficient mice, and the in vivo effects of C16 on tumorigenesis were examined. C16 suppressed proliferation of HCC cells in a dose-dependent manner in vitro. Mouse models with xenograft transplantation showed that the inhibitor suppressed the growth of HCC cells in vivo. Moreover, C16 decreased angiogenesis in HCC tissue in the xenograft model. Consistent with these results in mice, transcript levels of vascular endothelial growth factor-A and factor-B, platelet-derived growth factor-A and factor-B, fibroblast growth factor-2, epidermal growth factor, and hepatocyte growth factor, which are angiogenesis-related growth factors, were significantly decreased by C16 in vitro. In conclusion, the PKR inhibitor C16 blocked tumor cell growth and angiogenesis via a decrease in mRNA levels of several growth factors. C16 may be useful in the treatment of HCC.

Lenvatinib has anti-tumor activity against advanced hepatocellular carcinoma (HCC). Hypothyroidism is also a frequent complication in patients treated with lenvatinib. However, studies on lenvatinib-induced thyroid toxicity and destructive thyroiditis are limited. Therefore, this study aimed to clarify the frequency and timing of thyroid abnormalities in lenvatinib for unresectable HCC. This retrospective study enrolled 50 patients with advanced HCC treated with lenvatinib. Patients were classified to have euthyroid, subclinical hypothyroidism, overt hypothyroidism, and thyrotoxicosis. The timing of thyroid dysfunction was assessed, and risk factors for incident hypothyroidism or thyrotoxicosis were evaluated using multivariate models. Subclinical hypothyroidism, overt hypothyroidism, and thyrotoxicosis occurred in 7 (14.0%), 26 (52.0%), and 5 (10.0%) patients, respectively. In the 33 patients with hypothyroidism, 27 (84.4%) developed the condition within 2 weeks of starting lenvatinib treatment. Of the 5 patients with thyrotoxicosis, 3 developed the condition within 8 weeks of starting lenvatinib administration. One patient developed thyrotoxicosis in only 1 week of the initiation of treatment. No correlation between the presence of antibodies and the incidence and severity of thyroid dysfunction due to the autoimmune mechanism was observed. The progression-free survival was significantly better in the hypothyroidism group. Lenvatinib treatment for unresectable HCC not only causes hypothyroidism, but also thyrotoxicosis. Moreover, these thyroid conditions develop within the early period of treatment at a higher prevalence. Patients with thyroid dysfunction had better prognosis. Based on these results, in patients administered with lenvatinib, there is need for careful assessment for the possibility of thyroid dysfunction from the onset of treatment.

Hepatic stellate cells (HSCs) were reported to promote the progression of hepatocellular carcinoma (HCC), however its mechanism is uncertain. We previously reported that protein kinase R (PKR) in hepatocytes regulated HCC proliferation. In this study, we focused on the role of PKR in HSCs, and clarified the mechanism of its association with HCC progression. We confirmed the activation of PKR in a human HSC cell line (LX-2 cell). IL-1β is produced from HSCs stimulated by lipopolysaccharide (LPS) or palmitic acid which are likely activators of PKR in non-alcoholic steatohepatitis (NASH). Production was assessed by real-time PCR and ELISA. C16 and small interfering RNA (siRNA) were used to inhibit PKR in HSCs. The HCC cell line (HepG2 cell) was cultured with HSC conditioning medium to assess HCC progression, which was evaluated by proliferation and scratch assays. Expression of PKR was increased and activated in stimulated HSCs, and IL-1β production was also increased molecular. Key molecules of the mitogen-activated protein kinase pathway were also upregulated and activated by LPS. Otherwise, PKR inhibition by C16 and PKR siRNA decreased IL-1β production. HCC progression was promoted by HSC-stimulated conditioning medium although it was reduced by the conditioning medium from PKR-inhibited HSCs. Moreover, palmitic acid also upregulated IL-1β expression in HSCs, and conditioning medium from palmitic acid-stimulated HSCs promoted HCC proliferation. Stimulated HSCs by activators of PKR in NASH could play a role in promoting HCC progression through the production of IL-1β, via a mechanism that seems to be dependent on PKR activation., Competing Interests: The authors have declared that no competing interests exist.

Background: Although sorafenib-regorafenib sequential therapy improves the prognosis of patients with hepatocellular carcinoma (HCC), many patients abandon sequential therapy due to worsening hepatic reserve function. Thus, it is important to clarify which patients can be treated using regorafenib. The albumin-bilirubin score is a good biomarker for hepatic reserve function. The aim of this study was to determine whether patient albumin-bilirubin scores at the start of sorafenib treatment could be used to identify candidates for subsequent regorafenib therapy., Methods: This is a retrospective cohort study. From 2009 to 2017, 267 hepatocellular carcinoma patients treated with sorafenib were enrolled. After sorafenib therapy, 138 progressive disease patients were analyzed. The patients were divided in two groups: (i) regorafenib candidate group (Child-Pugh class A, Eastern Cooperative Oncology Group Performance Status ≤1, and maintained sorafenib tolerance); and (ii) regorafenib non-candidate group. The primary endpoint was the albumin-bilirubin score. We assessed retrospectively whether albumin-bilirubin scores were useful for predicting regorafenib treatment regimen candidacy., Results: For the 138 analyzed patients, the median overall survival duration was 15.6 months in the regorafenib candidate group and 6.8 months in the regorafenib non-candidate group (P < 0.01). Using univariate analysis, etiology, aspartate aminotransferase ≥40 IU/L, prothrombin time ≥85% and albumin-bilirubin score <-2.53 at the start of sorafenib treatment were identified as predictors. Using multivariate analysis, albumin-bilirubin score <-2.53 was the only significant predictor., Conclusions: Based on the multivariate analysis results, albumin-bilirubin score at the start of sorafenib therapy is a useful marker for identifying candidate patients for starting regorafenib therapy.

Double-stranded (ds) RNA-dependent protein kinase (PKR) is a ubiquitously expressed serine/threonine protein kinase. It was initially identified as an innate immune antiviral protein induced by interferon (IFN) and activated by dsRNA. PKR is recognized as a key executor of antiviral host defense. Moreover, it contributes to inflammation and immune regulation through several signaling pathways. In addition to IFN and dsRNA, PKR is activated by multiple stimuli and regulates various signaling pathways including the mitogen-activated protein kinase (MAPK) and nuclear factor kappa-light-chain-enhancer of activated B cells pathways. PKR was initially thought to be a tumor suppressor as a result of its ability to suppress cell growth and interact with major tumor suppressor genes. However, in several types of malignant disease, such as colon and breast cancers, its role remains controversial. In hepatocellular carcinoma, hepatitis C virus (HCV) is the main cause of liver cancer, and PKR inhibits HCV replication, indicating its role as a tumor suppressor. However, PKR is overexpressed in cirrhotic patients, and acts as a tumor promoter through enhancement of cancer cell growth by mediating MAPK or signal transducer and activator of transcription pathways. Moreover, PKR is reportedly required for the activation of inflammasomes and influences metabolic disorders. In the present review, we introduce the multifaceted roles of PKR such as antiviral function, tumor cell growth, regulation of inflammatory immune responses, and maintaining metabolic homeostasis; and discuss future perspectives on PKR biology including its potential as a therapeutic target for liver cancer., (© 2018 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)

Background and Aim: The aim of this study is to confirm the efficacy of multipolar ablation with a new simulator system, three-dimensional (3-D) sim-Navigator, for patients with hepatocellular carcinoma by assessing relapse-free survival and shape of the ablation volume under clinical conditions., Methods: All participants provided written, informed consent, and study protocols were approved by the institutional ethics committee. Twenty-seven patients with 27 nodules were treated by no-touch ablation using the new simulator system. Another 21 patients with 21 nodules treated without the simulator system were enrolled as controls. Tumor progression and shape of ablation volume were assessed. Predictors of tumor progression were assessed by Cox proportional hazard model., Results: No significant differences in clinical characteristics were seen between groups. Mean sphericity was 0.48 ± 0.07 with 3-D sim-Navigator and 0.37 ± 0.07 without 3-D sim-Navigator (P < 0.001). Median surface-to-volume ratio and compactness were also significantly closer to those of a sphere with 3-D sim-Navigator (P = 0.017, P < 0.001). Relapse-free survival rates at 1 and 1.5 years were 94.1% and 82.4%, respectively, with 3-D sim-Navigator, compared with 83.2% and 55.5% without (P = 0.056). The only independent factor predicting relapse-free survival was use of 3-D sim-Navigator (hazard ratio, 0.12; 95%CI, 0.01-0.87; P = 0.035)., Conclusions: Ideal ablation area was acquired by this simulation and navigation system in clinics. This system improved local tumor progression by facilitating appropriate insertion of multiple electrodes., (© 2017 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.)

The acidic (leucine-rich) nuclear phosphoprotein 32 family member B (ANP32B), a highly conserved member of the acidic nuclear phosphoprotein 32 (ANP32) family, is critical for the development of normal tissue. However, its role in the development of hepatocellular carcinoma (HCC) is controversial. In this study, we elucidated the role of ANP32B in HCC cell lines and tissues. ANP32B expression in HCC cell lines was modulated using siRNA and ANP32B expression plasmids and lentiviruses. The levels of apoptosis-related proteins were analyzed by real-time RT-PCR and Western blotting. The expression of ANP32B in tissues from patients with HCC was investigated using real-time RT-PCR and immunohistochemistry. ANP32B knockdown by siRNA altered the expression of apoptosis-related proteins in HCC cell lines and reduced the expression of cleaved forms of caspase 3 and caspase 9, but not that of caspase 8, in HCC cells cultured with the pro-apoptotic agent staurosporine. Phosphorylated Bad was upregulated, whereas Bak was downregulated. Moreover, ABT-737, which binds to and inhibits anti-apoptotic proteins of the Bcl-2 family, rendered HCC cells resistant to apoptosis induced by ANP32B silencing. Conversely, ANP32B overexpression decreased Bad phosphorylation and upregulated Bak, but did not induce apoptosis because Bax expression was downregulated. In tissues from patients with HCC, a low tumor/non-tumor ratio of ANP32B mRNA expression was related to advanced UICC stage (p = 0.032). TUNEL-positive cells were observed in parallel with ANP32B expression in HCC tissues. ANP32B modulates Bad phosphorylation as well as Bak and Bax expression, resulting in regulation of apoptosis in HCC. These findings indicate the potential value of ANP32B as a therapeutic target for HCC.

Background and Aim: Entecavir is one of the most-used nucleoside analogues for the treatment of patients with chronic hepatitis B virus (HBV) infection. The aim of this study was to clarify the effects of long-term entecavir treatment on the incidence of hepatocellular carcinoma (HCC)., Methods: The participants were 249 patients with chronic HBV infection who had been treated by entecavir for more than 2 years. Hepatic functional reserve and incidence of HCC were evaluated, and the factors that might contribute to the development of HCC were analyzed., Results: Prothrombin activity was significantly elevated at 60 months after starting entecavir (from 85.9 ± 17.4 to 97.0 ± 16.9%, p < 0.001). The albumin level was also significantly elevated at 60 months after starting entecavir (from 4.0 ± 0.5 to 4.3 ± 0.3 mg/dL, p < 0.001). The annual incidence of HCC decreased over time, and the incidence of HCC was only 1.8% at 5 years after starting entecavir. On multivariate analysis for HCC incidence, older age and low platelet count were significant, independent contributing factors., Conclusions: Long-term treatment with entecavir improved hepatic functional reserve and decreased the incidence of HCC over time after 3 years. To decrease the incidence of HCC, careful induction of long-term entecavir treatment in younger patients with chronic HBV infection and better hepatic functional reserve would be important.

Multipuncture radiofrequency ablation is expected to produce a large ablated area and reduce intrahepatic recurrence of hepatocellular carcinoma; however, it requires considerable skill. This study evaluated the utility of a new simulator system for multipuncture radiofrequency ablation. To understand positioning of multipuncture electrodes on three-dimensional images, we developed a new technology by expanding real-time virtual ultrasonography. We performed 21 experimental punctures in phantoms. Electrode insertion directions and positions were confirmed on computed tomography, and accuracy and utility of the simulator system were evaluated by measuring angles and intersections for each electrode. Moreover, to appropriately assess placement of the three electrodes, puncture procedures with or without the simulator were performed by experts and non-experts. Technical success was defined as maximum angle and distance ratio, as calculated by maximum and minimum distances between electrodes. In punctures using 2 electrodes, correlations between angles on each imaging modality were strong (ultrasound vs. simulator: r = 0.991, p<0.001, simulator vs. computed tomography: r = 0.991, p<0.001, ultrasound vs. computed tomography: r = 0.999, p<0.001). Correlations between distances in each imaging modality were also strong (ultrasound vs. simulator: r = 0.993, p<0.001; simulator vs. computed tomography: r = 0.994, p<0.001; ultrasound vs. computed tomography: r = 0.994, p<0.001). In cases with 3 electrodes, distances between each electrode correlated strongly (yellow-labeled vs. red-labeled: r = 0.980, p<0.001; red-labeled vs. blue-labeled: r = 0.953, p<0.001; yellow-labeled vs. blue-labeled: r = 0.953, p<0.001). Both angle and distance ratio (expert with simulator vs. without simulator; p = 0.03, p = 0.02) were significantly smaller in procedures performed by experts using the simulator system. The new simulator system appears to accurately guide electrode positioning. This simulator system could allow multipuncture radiofrequency ablation to be performed more effectively and comfortably.

Bile duct injury is a potential complication of radiofrequency ablation (RFA). Bipolar RFA devices have recently become available. Because visibility of the bipolar RFA electrodes is not good on ultrasonography, more careful usage of the electrodes to avoid bile ducts is needed. We present a case with hepatocellular carcinoma (HCC) located near the B5 intrahepatic bile duct. To view the bile duct, we used contrast medium for ultrasonography, administered through a biliary drainage catheter for endoscopic nasobiliary drainage (ENBD). Infusing the contrast medium allowed clear visualization of the HCC adjacent to the major bile duct during RFA. We also used a navigation system for bipolar RFA to confirm positions of the electrodes and HCC. We confirmed complete ablation of the HCC while avoiding bile duct injury and late bile duct stenosis. Administration of contrast medium for ultrasonography through an ENBD tube appears useful to avoid bile duct injury during RFA.

A 62-year-old woman with hepatocellular carcinoma (HCC) and asthma presented with acute abdominal pain and a decreased hemoglobin level. Peritoneal fluid was detected around the lesion, and rupture was suspected based on the findings of computed tomography. Extravasation of the HCC tumor was not detected on angiography with iodine contrast agent; however, such extravasation was clearly observed on angiography with carbon dioxide (CO2). CO2 angiography is sometimes utilized in patients with arterial bleeding. This modality be more effective and safe than angiography with iodine contrast agent for assessing potential ruptured HCC lesions.

Double-stranded RNA-activated protein kinase R (PKR) is known to be upregulated by hepatitis C virus (HCV) and overexpressed in hepatocellular carcinoma (HCC). However, the precise roles of PKR in HCC with HCV infection remain unclear. Two HCV replicating cell lines (JFH-1 and H77s), generated by transfection of Huh7.5.1 cells, were used for experiments reported here. PKR expression was modulated with siRNA and a PKR expression plasmid, and cancer-related genes were assessed by real-time PCR and Western blotting; cell lines were further analyzed using a proliferation assay. Modulation of genes by PKR was also assessed in 34 human HCC specimens. Parallel changes in c-Fos and c-Jun gene expression with PKR were observed. Levels of phosphorylated c-Fos and c-Jun were upregulated by an increase of PKR, and were related to levels of phosphorylated JNK1 and Erk1/2. DNA binding activities of c-Fos and c-Jun also correlated with PKR expression, and cell proliferation was dependent on PKR-modulated c-Fos and c-Jun expression. Coordinate expression of c-Jun and PKR was confirmed in human HCC specimens with HCV infection. PKR upregulated c-Fos and c-Jun activities through activation of Erk1/2 and JNK1, respectively. These modulations resulted in HCC cell proliferation with HCV infection. These findings suggest that PKR-related proliferation pathways could be an attractive therapeutic target.

It has occasionally been reported that mechanical trauma and posttraumatic inflammation may promote metastasis from a primary tumor to the site of the trauma. However, the etiologies that contribute to the metastasis formation at the trauma site remain unknown. We describe here the first case of skull metastasis from hepatocellular carcinoma (HCC) revealing a growing subcutaneous mass at the site of skull fracture. A 58-year-old man had undergone surgical resection of a primary tumor in the liver 2 years previously and was in clinical remission. The patient fell head first off his bicycle and suffered a skull fracture in the squamous portion of the left temporal bone without ostelysis. Three months after the head trauma, he presented at our department with a growing lump on the left side of his head, and magnetic resonance (MR) imaging revealed an osteolytic tumor extending into the adjacent subcutaneous and epidural space. The tumor was at the same location as the skull fracture sustained in the bicycle accident. The mass lesion was radically resected with surrounding normal bone. The tumor formed a well-demarcated mass with osteolysis of the inner and outer skull tables, and the inner layer of the dura mater was intact. The histological diagnosis for the surgical specimen from the skull tumor was a HCC identical to the primary tumor. Immunohistochemically, the tumor cells were diffusely and strongly positive for vascular endothelial growth factor (VEGF) and basic fibrous growth factor (bFGF). It is well known that the extracellular matrix and cytokines are involved in the processes of not only bone healing but also metastasis formation. The present case suggests that several processes involved in bone healing modified the microenvironment and represent a possible cause of skull metastasis from primary tumor.