A phase 2 multicenter study of stereotactic body radiotherapy for hepatocellular carcinoma: Safety and efficacy.

BACKGROUND: Although several prospective studies have reported the efficacy of stereotactic body radiotherapy (SBRT) for hepatocellular carcinoma (HCC), treatment-related toxicity varies and has not been determined. Therefore, the authors evaluated the safety and efficacy of SBRT for patients with HCC in a hepatitis B virus-endemic area. METHODS: This multicenter phase 2 trial enrolled patients with unresectable HCC. Patients received SBRT with 45 to 60 Gy in 3 fractions. To evaluate gastroduodenal toxicity, esophagogastroduodenoscopy (EGD) was performed before and 2 months after SBRT. The primary endpoint was treatment-related severe toxicity at 1 year after SBRT. The secondary endpoints were the 2-year local control, progression-free survival, and overall survival rates. RESULTS: In total, 74 patients were enrolled between January 2012 and April 2015, and 65 eligible patients were analyzed. One patient experienced radiation-induced liver disease with acute grade ≥3 toxicity 1 month after SBRT. In addition, 1 patient had a grade 3 esophageal ulcer with stenosis 5 months after SBRT. The actuarial rate of treatment-related severe toxicity at 1 year was 3%. The pre-SBRT and post-SBRT EGD findings were not significantly different among the 57 evaluable patients who underwent EGD. The 2-year and 3-year local control rates were 97% and 95%, respectively. The progression-free and overall survival rates were 48% and 84% at 2 years, respectively, and 36% and 76% at 3 years, respectively. CONCLUSIONS: With a median follow-up of 41 months, this prospective multicenter study demonstrated that SBRT for patients with HCC is well tolerated and is an effective treatment modality.

Recurrence-associated pathways in hepatitis B virus-positive hepatocellular carcinoma.

BACKGROUND: Despite the recent identification of several prognostic gene signatures, the lack of common genes among experimental cohorts has posed a considerable challenge in uncovering the molecular basis underlying hepatocellular carcinoma (HCC) recurrence for application in clinical purposes. To overcome the limitations of individual gene-based analysis, we applied a pathway-based approach for analysis of HCC recurrence. RESULTS: By implementing a permutation-based semi-supervised principal component analysis algorithm using the optimal principal component, we selected sixty-four pathways associated with hepatitis B virus (HBV)-positive HCC recurrence (p < 0.01), from our microarray dataset composed of 142 HBV-positive HCCs. In relation to the public HBV- and public hepatitis C virus (HCV)-positive HCC datasets, we detected 46 (71.9%) and 18 (28.1%) common recurrence-associated pathways, respectively. However, overlap of recurrence-associated genes between datasets was rare, further supporting the utility of the pathway-based approach for recurrence analysis between different HCC datasets. Non-supervised clustering of the 64 recurrence-associated pathways facilitated the classification of HCC patients into high- and low-risk subgroups, based on risk of recurrence (p < 0.0001). The pathways identified were additionally successfully applied to discriminate subgroups depending on recurrence risk within the public HCC datasets. Through multivariate analysis, these recurrence-associated pathways were identified as an independent prognostic factor (p < 0.0001) along with tumor number, tumor size and Edmondson's grade. Moreover, the pathway-based approach had a clinical advantage in terms of discriminating the high-risk subgroup (N = 12) among patients (N = 26) with small HCC (<3 cm). CONCLUSIONS: Using pathway-based analysis, we successfully identified the pathways involved in recurrence of HBV-positive HCC that may be effectively used as prognostic markers.

Clinical outcomes of early gastric cancer with lymphovascular invasion or positive vertical resection margin after endoscopic submucosal dissection.

BACKGROUND: In early gastric cancer (EGC) cases with lymphovascular invasion or positive vertical margins after endoscopic submucosal dissection (ESD), additional radical gastrectomy is performed on principle. However, an additional surgery is often difficult to consider if the surgical approach itself is challenging or the patient refuses surgery. In such cases, only close surveillance is performed without additional surgical procedures. This study aimed to examine the difference in clinical prognosis of EGC cases with lymphovascular invasion or positive vertical margins after ESD either with or without surgery. METHODS: We retrospectively studied 83 patients with lymphovascular invasion or positive vertical margins after ESD from July 2005 to November 2013. RESULTS: Of the 83 patients, 45 (54.2%) underwent radical additional gastrectomy (surgical group) and 38 (45.8%) were under close surveillance without surgical or endoscopic treatments (close surveillance group.) The cancer-free survival period was 78.3 ± 3.4 months in the surgical group and 64.5 ± 4.6 months in the close surveillance group. The recurrence rates did not significantly differ between the 2 groups, at 7.9% in the surgical group and 6.7% in the non-surgical group. CONCLUSIONS: Close surveillance may be suggested as an option for EGC patients for whom a surgical approach is difficult, who exhibit a positive vertical margin after ESD, and who have no lymphovascular or deep submucosa invasion after ESD.

Low Hepatic Toxicity in Primary and Metastatic Liver Cancers after Stereotactic Ablative Radiotherapy Using 3 Fractions.

This study evaluated the incidence of hepatic toxicity after stereotactic ablative radiotherapy (SABR) using 3 fractions to the liver, and identified the predictors for hepatic toxicity. We retrospectively reviewed 78 patients with primary and metastatic liver cancers, who underwent SABR using 3 fractions between 2003 and 2011. To examine the incidence of hepatic toxicity, we defined newly developed hepatic toxicity≥grade 2 according to the National Cancer Institute Common Terminology Criteria for Adverse Events v4.0 within 3 months after the end of SABR as a significant adverse event. To identify the predictors for hepatic toxicity, we analyzed several clinical and dosimetric parameters (rV5Gy-rV35Gy: normal liver volume receiving

Hedgehog signaling between cancer cells and hepatic stellate cells in promoting cholangiocarcinoma.

BACKGROUND: Aberrant Hedgehog (HH) signaling activation is important in cancer growth and mediates the interaction between cancer cells and the surrounding stromal cells. This study investigated the role of HH signaling on the growth of cholangiocarcinoma (CC), focusing on the interaction of CC cells with stromal cells. METHODS: To evaluate the interaction between human CC cells (SNU-1196, SNU-246, SNU-308, SNU-1079, and HuCCT-1) and stromal cells (hepatic stellate cell line, Lx-2), co-culture proliferation, migration, and invasion assays were performed. In vivo nude mice experiments were conducted using two groups-HuCCT-1 single implant xenograft (SX) and co-implant xenograft (CX) with HuCCT-1 and Lx-2. RESULTS: When HuCCT-1 cells were co-cultured with Lx-2 cells, the expression of HH signaling-related proteins increased in both HuCCT-1 and Lx-2 cells. Co-culture with Lx-2 cells stimulated the proliferation, migration, and invasion of CC cells, and these effects were mediated by HH signaling. Co-culture of HuCCT-1 and Lx-2 cells increased the secretion of several cytokines. In an ectopic xenograft model, Lx-2 co-implantation increased CC tumor growth and stimulated angiogenesis. Cyclopamine attenuated tumor growth in the CX group, but not in the HuCCT-1 mono-implant (SX) group. Cyclopamine treatment decreased CC cell proliferation, suppressed microvessel density, and increased tumor necrosis in the CX group, but not in the SX group. CONCLUSION: Hepatic stellate cells stimulate the proliferation, migration, and invasion of CC cells, promote angiogenesis through HH signaling activation, and render CC more susceptible to necrosis by HH inhibitor.

Clinical result of stereotactic radiosurgery for spinal metastasis from hepatocellular carcinoma: comparison with conventional radiation therapy.

We investigated the clinical outcome following stereotactic radiosurgery (SRS) for spinal metastasis from hepatocellular carcinoma (HCC) and compared it with that of conventional radiation therapy (cRT). Thirty-nine metastatic spine tumors from 27 HCC patients were treated with SRS from 2002 to 2011. Their medical records and radiological data were retrospectively analyzed. Median tumor volume was 49.7 cc, and a mean marginal dose of 28.7 Gy was delivered to the tumor mass. We analyzed overall survival (OS), local progression-free survival, and the rate of pain control following SRS. Factors relating to clinical outcomes were also investigated. Clinical results following cRT were obtained from 32 patients. The cRT protocol consisted of 30 Gy in 10 fractions or 39 Gy in 13 fractions. OS and local progression-free survival were compared between SRS and cRT. OS was a median of 7 months following SRS. Significant prognostic factors relating to OS included Child-Pugh class and Karnofsky performance scale. Tumor recurrence was noted in nine lesions during follow-up. The median local progression-free survival was 7 months. Previous irradiation was a significant prognostic factor for local recurrence (P = 0.043). The overall pain control rate was 85 % and no factors were found to be significantly correlated with the pain control rate. The median OS was 3 months in the cRT group and 7 months in the SRS group (P = 0.035). The median local progression-free survival was 2.0 months in the cRT group, and 7.0 months in the SRS group, which were significantly different (P = 0.033). SRS showed better local control than cRT in the treatment of HCC spinal metastasis.

Depletion of proteasome subunit PSMD1 induces cancer cell death via protein ubiquitination and DNA damage, irrespective of p53 status.

Hepatocellular carcinoma (HCC) is characterized by high incidence and fatality rates worldwide. In our exploration of prognostic factors in HCC, the 26s proteasome subunit, non-ATPase 1 (PSMD1) protein emerged as a significant contributor, demonstrating its potential as a therapeutic target in this aggressive cancer. PSMD1 is a subunit of the 19S regulatory particle in the 26S proteasome complex; the 19S particle controls the deubiquitination of ubiquitinated proteins, which are then degraded by the proteolytic activity of the complex. Proteasome-targeting in cancer therapy has received significant attention because of its practical application as an established anticancer agent. We investigated whether PSMD1 plays a critical role in cancer owing to its prognostic significance. PSMD1 depletion induced cell cycle arrest in G2/M phase, DNA damage and apoptosis of cancer cells, irrespective of the p53 status. PSMD1 depletion-mediated cell death was accompanied by an increase in overall protein ubiquitination. These phenotypes occurred exclusively in cancer cells, with no effects observed in normal cells. These findings indicate that PSMD1 depletion-mediated ubiquitination of cellular proteins induces cell cycle arrest and eventual death in cancer cells, emphasizing PSMD1 as a potential therapeutic target in HCC.

Overexpression of Romo1 promotes production of reactive oxygen species and invasiveness of hepatic tumor cells.

BACKGROUND & AIMS: Chronic oxidative stress from reactive oxygen species (ROS) produced by the mitochondria promotes hepatocarcinogenesis and tumor progression. However, the exact mechanism by which mitochondrial ROS contributes to tumor cell invasion is not known. We investigated the role of ROS modulator 1 (Romo1) in hepatocellular carcinoma (HCC) development and tumor cell invasiveness. METHODS: We performed real-time, semi-quantitative, reverse transcriptase polymerase chain reaction; invasion and luciferase assays; and immunofluorescence and immunohistochemical analyses. The formation of pulmonary metastatic nodules after tumor cell injection was tested in severe combined immunodeficient mice. We analyzed Romo1 expression in HCC cell lines and tissues (n = 95). RESULTS: Expression of Romo1 was increased in HCC cells, compared with normal human lung fibroblast cells. Exogenous expression of Romo1 in HCC cells increased their invasive activity, compared with control cells. Knockdown of Romo1 in Hep3B and Huh-7 HCC cells reduced their invasive activity in response to stimulation with 12-O-tetradecanoylphorbol-13-acetate. Levels of Romo1 were increased compared with normal liver tissues in 63 of 95 HCC samples from patients. In HCC samples from patients, there was an inverse correlation between Romo1 overexpression and patient survival times. Increased levels of Romo1 also correlated with vascular invasion by the tumors, reduced differentiation, and larger tumor size. CONCLUSIONS: Romo1 is a biomarker of HCC progression that might be used in diagnosis. Reagents that inhibit activity of Romo1 and suppress mitochondrial ROS production, rather than eliminate up-regulated intracellular ROS, might be developed as cancer therapies.

Severe intestinal toxicity after stereotactic ablative radiotherapy for abdominopelvic malignancies.

PURPOSE: The purpose of this study is to identify the predictors for severe intestinal toxicity (IT) in patients with abdominopelvic malignancies treated with three fractions of stereotactic ablative radiotherapy (SABR). METHODS: From 2001 to 2011, 202 patients with abdominopelvic malignancies were treated with curative-intent SABR. Among these, we retrospectively reviewed the clinical records of 55 patients with the presence of the intestine that received a dose ≥20 % of the prescribed dose. The total dose ranged from 33 to 60 Gy in three fractionations (median dose, 45 Gy). We analyzed the clinical and dosimetric parameters for severe IT ≥ grade 3 according to the National Cancer Institute Common Toxicity Criteria v4.0: V(20-35) (volume of the intestine that received xGy) and D(max) (maximum point dose). RESULTS: Severe IT was found in six patients (the median time, 3 months). V(25) was the best dosimetric predictor for severe IT (P = 0.004). With V(25) ≤ 20 ml, severe IT decreased from 50 to 4 %. SABR duration was the best clinical predictor. Severe IT decreased in patients who received SABR at 4-8 days than on three consecutive days (0 vs. 18 %, P = 0.037). CONCLUSIONS: Following three fractions of SABR, V(25) is a valuable predictor of severe IT. And SABR would be conducted with a treatment interval of at least 48 h if possible.

Feasibility and efficacy of stereotactic ablative radiotherapy for Barcelona Clinic Liver Cancer-C stage hepatocellular carcinoma.

The purpose of this study was to assess the feasibility and efficacy of stereotactic ablative radiotherapy (SABR) for liver tumor in patients with Barcelona Clinic Liver Cancer (BCLC)-C stage hepatocellular carcinoma (HCC). We retrospectively reviewed the medical records of 35 patients between 2003 and 2011. Vascular invasion was diagnosed in 32 patients, extrahepatic metastases in 11 and both in 8. Thirty-two patients were categorized under Child-Pugh (CP) class A and 3 patients with CP class B. The median SABR dose was 45 Gy (range, 30-60 Gy) in 3-5 fractions. The median survival time was 14 months. The 1- and 3-yr overall survival (OS) rate was 52% and 21%, respectively. On univariate analysis, CP class A and biologically equivalent dose ≥ 80 Gy(10) were significant determinants of better OS. Severe toxicity above grade 3, requiring prompt therapeutic intervention, was observed in 5 patients. In conclusion, SABR for BCLC-C stage HCC showed 1-yr OS rate of 52% but treatment related toxicity was moderate. We suggest that patients with CP class A are the best candidate and at least SABR dose of 80 Gy(10) is required for BCLC-C stage.

Stereotactic body radiation therapy for inoperable hepatocellular carcinoma as a local salvage treatment after incomplete transarterial chemoembolization.

BACKGROUND: The objective of this study was to evaluate the efficacy and safety of stereotactic body radiation therapy (SBRT) as a local salvage treatment after incomplete transarterial chemoembolization (TACE) for inoperable hepatocellular carcinoma (HCC). METHODS: The main eligibility criteria were a greatest tumor dimension (LD sum) <10 cm, inoperable HCC, and incomplete response after TACE. Prescribed SBRT doses were up to 60 gray (Gy) in 3 fractions, but doses were reduced until normal tissue constraints were allowed. RESULTS: Between May 2008 and February 2011, 50 patients were enrolled in this phase 2 trial, of which 47 patients were evaluable. Forty-one patients had Child-Pugh class A disease (A5/A6 were 32/9), 6 patients had class B7 disease, and 5 patients had portal vein tumor thrombosis. All patients underwent TACE 1 to 5 times before SBRT. SBRT doses ranged from 42 to 60 Gy in 3 fractions (median dose, 57 Gy), and the median LD sum was 29 mm (range, 13-78 mm). Eighteen patients (38.3%) achieved complete remission within 6 months of completing of SBRT, and 18 patients (38.3%) had a partial response. The 2-year local control rate was 94.6%, the overall survival rate was 68.7%, and the progression-free survival rate was 33.8%. Three patients (6.4%) experienced grade 3 gastrointestinal toxicity, and 2 patients (4.3%) experienced grade 4 gastric ulcer perforation. CONCLUSIONS: This trial demonstrated that SBRT after incomplete TACE for inoperable HCC achieves promising rates of response and local control. On the basis of these study results, a modified, multi-institutional, phase 2 trial to reduce gastrointestinal toxicity is recommended.

Integrated analysis of prognostic gene expression profiles from hepatitis B virus-positive hepatocellular carcinoma and adjacent liver tissue.

BACKGROUND: The tissue environment in the region of hepatocellular carcinoma (HCC) influences both vascular invasion and recurrence. Thus, HCC patient prognosis depends on the characteristics not only of the tumor but also those of adjacent surrounding liver tissue. MATERIALS AND METHODS: Expression profiles of both tumor and adjacent liver tissue following curative resection were measured to discriminate 56 hepatitis B virus-positive HCC patients into subgroups based on survival risk. This approach was further tested in 40 patients. RESULTS: Expression profiles of both tumor and adjacent liver tissue successfully discriminated 56 training samples into 2 subgroups, those at low- or high-risk for survival and recurrence. However, the prognostic gene set selected for tumor tissue was quite different from that for adjacent tissues. This variation in prognostic genes resulted in a change in allocation of patients within each low- or high-risk group. Combination of survival subgroups from tumor and adjacent liver tissue significantly improved the prediction of prognostic outcome. This integrative approach was confirmed to be effective in a further 40 test patients. A clinicopathological study showed that survival subgroups divided by tumor and adjacent liver tissue gene expression were also statistically associated with UICC stage and extent of cell differentiation, respectively. CONCLUSIONS: Variation in gene expression during the nontumor stage as well as the tumor stage may affect the prognosis of HCC patients, and integration of the gene expression profiles of HCC and adjacent liver tissue increases discriminatory effectiveness between patient groups, predicting clinical outcomes with enhanced statistical reliability.

NPFFR2 Contributes to the Malignancy of Hepatocellular Carcinoma Development by Activating RhoA/YAP Signaling.

G protein-coupled receptors (GPCRs) are a diverse family of cell surface receptors implicated in various physiological functions, making them common targets for approved drugs. Many GPCRs are abnormally activated in cancers and have emerged as therapeutic targets for cancer. Neuropeptide FF receptor 2 (NPFFR2) is a GPCR that helps regulate pain and modulates the opioid system; however, its function remains unknown in cancers. Here, we found that NPFFR2 is significantly up-regulated in liver cancer and its expression is related to poor prognosis. Silencing of NPFFR2 reduced the malignancy of liver cancer cells by decreasing cell survival, invasion, and migration, while its overexpression increased invasion, migration, and anchorage-independent cell growth. Moreover, we found that the malignant function of NPFFR2 depends on RhoA and YAP signaling. Inhibition of Rho kinase activity completely restored the phenotypes induced by NPFFR2, and RhoA/F-Actin/YAP signaling was controlled by NPFFR2. These findings demonstrate that NPFFR2 may be a potential target for the treatment of hepatocellular carcinoma.

Preliminary result of stereotactic body radiotherapy as a local salvage treatment for inoperable hepatocellular carcinoma.

BACKGROUND AND OBJECTIVES: To evaluate the toxicity and efficacy of stereotactic body radiotherapy (SBRT) for the treatment of localized hepatocellular carcinoma (HCC) in the absence of another standard treatment option. METHODS: The authors reviewed the details of 38 patients with inoperable HCC (diameter <10 cm) treated by SBRT in a prospectively registered database at their institution. All patients had been treated by transcatheter arterial chemoembolization before SBRT, which had been finally deemed ineffective. SBRT dosages (33-57 Gy in three or four fractions) were administered according to tumor volumes, which ranged from 11 to 464 ml (median, 40.5 ml). RESULTS: Two-year overall survival and local progression-free survival rates were 61.4% and 66.4%, respectively. The local response rate was 63% at 3 months after SBRT. A high radiation dose was found to be independently related to survival. A decline in liver function was observed in six patients (16%) and Grade 3 musculoskeletal toxicity in one patient (2.7%). CONCLUSIONS: This study showed that SBRT can be safely administered to select HCC patients, and these results suggest that this technique should be considered a salvage treatment. A further well-controlled large-scale study and longer follow-up are needed to determine optimal dose-fraction schedules and characterize late complications.

Pilot study of stereotactic body radiotherapy for huge hepatocellular carcinoma unsuitable for other therapies.

AIMS: To determine the feasibility and efficacy of stereotactic body radiotherapy (SBRT) for huge hepatocellular carcinoma unsuitable for other therapies. METHODS: Six patients with very large hepatocellular carcinomas (>10 cm) unsuitable for surgical resection or that failed to respond to transcatheter arterial chemoembolization (TACE) were treated by SBRT. Doses ranged from 32 Gy to 40 Gy in four fractions. Survival, response, and toxicities were evaluated. RESULTS: After a median follow-up of 25.9 months (range 8.1-56 months), three patients had died and three were alive. Overall, treatment was well tolerated and no dose-limiting toxicity or radiation-induced liver disease was observed. The median survival was 10 months (range 3-56 months) and the median progression-free duration was 6 months (range, 2-21 months). Partial response was achieved by four patients, stable disease by one, and one patient had disease progression. One patient with a partial response who underwent lobectomy after SBRT was alive 56 months post-SBRT. CONCLUSION: This study suggests that SBRT can be delivered safely at 32-40 Gy in four fractions to huge hepatocellular carcinoma. Furthermore, combinations of SBRT with other modalities such as surgery or TACE might prolong survival.

[Recent developments in systemic chemotherapy for hepatocellular carcinoma].

Despite recent developments in various chemotherapeutic agents and the performing of numerous clinical trials, chemotherapy still produces unsatisfactory results in hepatocellular carcinoma due to poor clinical benefit compared with untreated controls and its significant toxicity. The presence of liver cirrhosis, its complications, and decreased liver function increase the complexity of chemotherapy. There is recent evidence that targeted agents and antiangiogenic agents such as thalidomide are somewhat effective whilst having minimal toxicities. Some patients are cured by aggressive chemotherapy alone or in combination with other modalities. Therefore, if a patient is in good condition and the tumor shows some response to chemotherapy, aggressive chemotherapy might be considered. Although conventional chemotherapeutic agents are not very effective in many patients, their utility might be improved by lowering toxicities using reduced doses or by selecting only responsive patients if adequate chemosensitivity tests are available. Imaging studies have been conventional tools for evaluating tumor responses, but their results are not always reliable. Establishing criteria for accurately determining tumor responses is urgently needed, along with better chemotherapeutic drugs and regimens.

TMEM165, a Golgi transmembrane protein, is a novel marker for hepatocellular carcinoma and its depletion impairs invasion activity.

Transmembrane protein 165 (TMEM165), a Golgi protein, functions in ion homeostasis and vesicular trafficking in the Golgi apparatus. While mutations in TMEM165 are known to cause human 'congenital disorders of glycosylation', a recessive autosomal metabolic disease, the potential association of this protein with human cancer development has not been explored to date. In the present study, we revealed that TMEM165 is overexpressed in HCC and its depletion weakens the invasive activity of cancer cells through suppression of matrix metalloproteinase­2 (MMP­2) expression. Levels of TMEM165 mRNA and protein were clearly increased in HCC patient tissues and cell cultures. Quantitative real­time RT­PCR analysis of fresh HCC tissues (n=88) revealed association of TMEM165 overexpression with more frequent macroscopic vascular invasion, microscopic serosal invasion and higher α­fetoprotein levels. Notably, depletion of TMEM165 led to a marked decrease in the invasive activity of two different HCC cell types, Huh7 and SNU475, accompanied by downregulation of MMP­2. Our collective findings clearly indicated that TMEM165 contributed to the progression of HCC by promoting invasive activity, supporting its utility as a novel biomarker and therapeutic target for cancer.

Protein arginine methyltransferase 5 is implicated in the aggressiveness of human hepatocellular carcinoma and controls the invasive activity of cancer cells.

Protein arginine methyltransferase 5 (PRMT5) is a protein that catalyzes transfer of methyl groups to the arginine residues of proteins and is involved in diverse cellular and biological responses. While the participation of PRMT5 in cancer progression has been increasingly documented, its association with the invasive phenotype currently remains poorly understood. In the present study, we revealed that PRMT5 is overexpressed in human hepatocellular carcinoma (HCC) and in colon cancer and its depletion leads to the suppression of cell invasive activity via the reduction of the expression of MMP-2. Real-time quantitative RT-PCR analysis of 120 HCC patient tissues revealed the overexpression of PRMT5 in HCC and the association of PRMT5 with aggressive clinicopathological parameters, such as poorer differentiation (P=0.004), more frequent hepatic vein invasion (P=0.019), larger tumor size (P=0.011) and higher α-fetoprotein levels (P=0.020). Similarly to the data obtained with HCC, overexpression of PRMT5 was also displayed in colon cancer tissues, compared to matched non-tumor regions. Consistent with the significant association of the overexpression of PRMT5 with hepatic vein invasion in patient specimens, PRMT5 depletion via siRNA transfection led to a marked reduction in the invasion rate in both HCC and colon cancer cells. Reduced invasion associated with PRMT5 depletion was accompanied by a decrease in the expression of MMP-2. Collectively, our results indicated that PRMT5 overexpression in HCC and colon cancer cells contributed to their acquisition of aggressive characteristics, such as invasiveness, thus presenting a promising therapeutic target for the treatment of these diseases.

Mutation analysis of p31comet gene, a negative regulator of Mad2, in human hepatocellular carcinoma.

Failure of mitotic checkpoint machinery leads to the chromosomal missegregation and nuclear endoreduplication, thereby driving the emergence of aneuploidy and tetraploidy population. Although abnormal nuclear ploidy and the resulting impairment of mitotic checkpoint function are typical physiological event leading to human hepatocellular carcinoma, any mutational change of mitotic checkpoint regulators has not yet been discovered. Therefore, we investigated the mutation of p31(comet), a recently identified mitotic checkpoint regulator, in human hepatocellular carcinoma. Of 51 human hepatocellular carcinoma tissue and 6 cell lines tested, five samples exhibited nucleotide sequence variations dispersed on four sites within the entire coding sequence. Among these sites with sequence substitutions, three were found to be missense mutation accompanied with amino acid change but one was a silent mutation. Of these sequence substitutions, two were present in both tumor and non-tumor liver tissues, suggesting the possibility of polymorphism. The present findings indicate that p31(comet) does not have an impact on the formation of aneuploidy and tetraploidy found in human hepatocellular carcinoma.