Bcl-2 expression is a poor predictor for hepatocellular carcinoma prognosis of andropause-age patients

OBJECTIVE

The expression of B-cell lymphoma 2 (Bcl-2) seems to be influenced by the endocrine environment. Numerous reports demonstrate the diverse expression of Bcl-2 family members under sex steroid regulation. With the exception of estrogen-related tumors, androgen-related tumors have shown their characteristics in Bcl-2 expression. In this study, the status of Bcl-2 expression in male hepatocellular carcinoma (HCC) patients was examined to verify the high incidence of HCC in males.

METHODS

Tumor tissue microarray was used to examine Bcl-2 expression levels in 374 HCC cases including 306 males and 68 females. Kaplan-Meier method, log-rank test, and Cox proportional hazards model were applied to investigate the predictive value of Bcl-2 in HCC patients.

RESULTS

Immunohistochemistry analysis showed that male patients with higher Bcl-2 levels had significantly longer median survival time and recurrence time than those with lower levels. However, no significant differences in outcomes were found between different Bcl-2 levels in female patients. When the male patients were stratified into several age points, the level of Bcl-2 expression showed poorer predictive efficiency in the 45-49 and 55-60 age groups in andropause-age patients compared with other age groups. Bcl-2 was an independent prognostic factor for both overall survival (P < 0.0001) and recurrence time (P = 0.0001) in male patients. After excluding male patients in the 45-60 age group, the predictive efficiency was enhanced (n = 147, OS, P = 0.0002, TTR, P < 0.0001).

CONCLUSIONS

Bcl-2 expression is an independent predictor of survival and recurrence in male HCC. Bcl-2 levels may also be regulated by androgens or androgen receptors in male HCC patients. Bcl-2 levels change and exhibit poor predictive efficiency when androgen levels vary dramatically (andropause age).

GOLM1 Modulates EGFR/RTK Cell-Surface Recycling to Drive Hepatocellular Carcinoma Metastasis

The mechanism of cancer metastasis remains poorly understood. Using gene profiling of hepatocellular carcinoma (HCC) tissues, we have identified GOLM1 as a leading gene relating to HCC metastasis. GOLM1 expression is correlated with early recurrence, metastasis, and poor survival of HCC patients. Both gain- and loss-of-function studies determine that GOLM1 acts as a key oncogene by promoting HCC growth and metastasis. It selectively interacts with epidermal growth factor receptor (EGFR) and serves as a specific cargo adaptor to assist EGFR/RTK anchoring on the trans-Golgi network (TGN) and recycling back to the plasma membrane, leading to prolonged activation of the downstream kinases. These findings reveal the functional role of GOLM1, a Golgi-related protein, in EGFR/RTK recycling and metastatic progression of HCC.

Interleukin-6 enhances cancer stemness and promotes metastasis of hepatocellular carcinoma via up-regulating osteopontin expression

Interleukin-6 (IL-6), one of the most important inflammatory cytokines, plays a pivotal role in metastasis and stemness of solid tumors. However, the underlying mechanisms of IL-6 in HCC metastasis remain unclear. In the present study, we demonstrated that stemness and metastatic potential of HCC cells were significantly enhanced after IL-6 stimulation. IL-6 could induce expression of osteopontin (OPN), along with other stemness-related genes, including HIF1α, BMI1, and HEY1. Block of OPN induction could significantly abrogate the effect of IL-6 on stemness and metastasis of HCC cells. Furthermore, IL-6 level was positively correlated with OPN in HCC. Patients with high plasma IL-6 or OPN level had poorer prognosis. In multivariate analysis, IL-6 and OPN were demonstrated to be independent prognostic indicators for HCC patients, and their combination had a better prognostic performance than IL-6 or OPN alone. Collectively, our findings indicate that IL-6 could enhance stemness and promote metastasis of HCC via up-regulating OPN expression, which can be a potential therapeutic target for combating HCC metastasis, and the combination of IL-6 and OPN serves as a promising prognostic predictor for HCC.

Hepatitis B virus and hepatitis C virus play different prognostic roles in intrahepatic cholangiocarcinoma: A meta-analysis

AIM: To identify the prognostic value of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections in patients with intrahepatic cholangiocarcinoma.

METHODS: A search was performed for relevant publications in PubMed, EMBASE and Web of Science databases. The pooled effects were calculated from the available information to identify the relationship between HBV or HCV infection and the prognosis and clinicopathological features. The χ² and I² tests were used to evaluate heterogeneity between studies. Pooled hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated by a fixed-effects model, if no heterogeneity existed. If there was heterogeneity, a random-effects model was applied.

RESULTS: In total, 14 studies involving 2842 cases were enrolled in this meta-analysis. The patients with HBV infection presented better overall and disease-free survival, and the pooled HRs were significant at 0.76 (95%CI: 0.70-0.83) and 0.78 (95%CI: 0.66-0.94), respectively. Additionally, our study revealed that HCV infection was correlated with shortened overall survival in comparison with the control group (HR = 2.64, 95%CI: 1.77-3.93). We also found that HBV infection occurred more frequently in male patients [odds ratio (OR) = 1.91, 95%CI: 1.06-3.44] and was correlated with higher levels of serum aspartate transaminase (AST) and alpha-fetoprotein (AFP) (OR = 1.93, 95%CI: 1.11-3.35; OR = 3.86, 95%CI: 2.58-5.78) and a lower level of serum carbohydrate antigen 19-9 (CA19-9) (OR = 0.47, 95%CI: 0.34-0.65). Moreover, HBV infection was associated with cirrhosis (OR = 6.44, 95%CI: 4.33-9.56), a higher proportion of capsule formation (OR = 6.04, 95%CI: 3.56-10.26), and a lower rate of lymph node metastasis (OR = 0.39, 95%CI: 0.25-0.58). No significant publication bias was seen in any of the enrolled studies.

CONCLUSION: HBV infection may indicate a favorable prognosis in patients with intrahepatic cholangiocarcinoma, while HCV infection suggests a poor prognosis.

Properties and feasibility of using cancer stem cells in clinical cancer treatment

Cancer treatment failure, drug resistance, or metastatic recurrence are thought to be caused mainly by the existence of a very small number of cancer stem cells (CSCs). The characteristics of this subgroup of cells include self-renewal, tumorigenesis, multiple differentiation and high invasiveness, metastasis, and drug resistance potential. Many studies have demonstrated that CSCs play important roles in tumor growth, spread and metastatic relapse after treatment, and are closely related to the prognosis of patients. From a therapeutic viewpoint, deep insights into the CSCs biology, development of specific therapeutic strategies for targeting CSCs, and characterization of their microenvironment could be an ideal way to combat cancer.

β-catenin mutation is correlated with a favorable prognosis in patients with hepatocellular carcinoma

The β-catenin gene is frequently mutated in patients with hepatocellular carcinoma (HCC) and has long been thought to be one of the major oncogenes involved in the hepatocarcinogenesis. The prognostic role of β-catenin mutation in HCC remains unclear. To address this issue, a search for relevant studies was performed in the PubMed, Embase and Web of Science databases. The pooled effect was calculated from the available data to evaluate the correlation of β-catenin mutation with overall survival rate and tumor clinicopathological features in patients with HCC. The pooled odds ratio (OR) was calculated using the Mantel-Haenszel model for fixed effects. Three studies met the inclusion criteria. A total of 618 cases were included, and β-catenin mutation was identified in 104 of them. The meta-analysis revealed that the presence of β-catenin mutation (n=104), compared with the control group (n=514), was correlated with a longer overall survival rate [OR, 0.33; 95% confidence interval (CI), 0.21-0.53; P<0.00001] in patients with HCC. No significant heterogeneity was found among the eligible studies (I²=0%; P=0.72). β-catenin mutation was correlated with a relatively lower rate of hepatitis B virus infection (OR, 0.36; 95% CI, 0.21-0.61; P=0.0002), improved tumor differentiation (OR, 0.32; 95% CI, 0.19-0.56; P<0.0001) and a lower tumor-node-metastasis stage (I+II) (OR, 0.23; 95% CI, 0.14-0.38; P<0.00001). These findings suggest that β-catenin mutation may predict a favorable prognosis in patients with HCC.

MicroRNA-26a suppresses angiogenesis in human hepatocellular carcinoma by targeting hepatocyte growth factor-cMet pathway

MicroRNA (miR)-26a can suppress tumor growth and metastasis of hepatocellular carcinoma (HCC). Since angiogenesis is important for tumor growth and metastasis, we investigated the possible roles of miR-26a in tumor angiogenesis. Down-regulation of miR-26a was found to correlate with an increased angiogenic potential of HCC. Through gain- and loss-of-function studies, miR-26a was demonstrated to significantly inhibit vascular endothelial growth factor A (VEGFA) expression in HCC cells and then suppress the promoting effects of HCC cells on in vitro proliferation, migration, and capillary tube formation of endothelial cells, as well as in vivo tumor angiogenesis of HCC. Hepatocyte growth factor (HGF) was identified as a target of miR-26a. HGF simulation antagonized the effects induced by miR-26a up-regulation. In contrast, silencing HGF induced similar effects to miR-26a. We further found that miR-26a exerted its antiangiogenesis function, at least in part, by inhibiting HGF-hepatocyte growth factor receptor (cMet) and its downstream signaling pathway, in turn, suppressing VEGFA production in HCC cells and impairing VEGFR2-signaling in endothelial cells. HCC patients who had high miR-26a, low HGF, low VEGFA, or low microvessel density (MVD) in tumor tissues had a better prognosis with longer overall survival (OS) and time to recurrence (TTR). In multivariate analysis, miR-26a, or in combination with HGF, was demonstrated to be an independent prognostic indicator for OS and TTR of HCC patients.

CONCLUSION

miR-26a could suppress tumor angiogenesis of HCC through HGF-cMet signaling, and it is a new hopeful therapeutic target and prognostic marker for HCC.

Genomic aberrations in the HTPAP promoter affect tumor metastasis and clinical prognosis of hepatocellular carcinoma

We previously reported that the intronic tagSNP +357G/C in the metastasis suppressor HTPAP is associated with metastasis and prognosis of hepatocellular carcinoma (HCC). The aim of this study was to investigate whether SNPs in the HTPAP promoter modulate HTPAP expression and prognosis of HCC. Genomic DNA from 572 microdissected HCCs were genotyped by pyrosequencing and verified by direct sequencing. Haplotype blocks were analyzed. Reporter plasmids were constructed and transfected into HCC cell lines. Transcriptional activities of plasmids were analyzed by dual-luciferase reporter systems. HTPAP expression was measured by real-time quantitative PCR, western blots, and tissue microarrays. Invasion was assessed by Matrigel assays. The prognostic values of HTPAP promoter SNPs in HCC were evaluated by Kaplan-Meier and Cox regression analyses. We identified six SNPs, including -1053A/G and +64G/C, in the HTPAP promoter. The SNPs were in complete linkage disequilibrium, resulting in three promoter haplotypes (promoter I:-1053AA/+64GG, promoter II: -1053AG/+64GC, and promoter III: -1053GG/+64CC). Promoter I manifested the highest luciferase index (p<0.005). However, no significant difference was observed between promoters II and III. We consistently found that HTPAP mRNA and protein levels were significantly higher in promoter I than that of promoter II+III (p<0.001). Invasion was increased in HCC cells transfected with promoters II+III compared to those transfected with promoter I (p<0.05). The HTPAP promoter II+III haplotype was associated with significantly increased metastasis compared to that of promoter I (p = 0.023). The postoperative five-year overall survival of patients with promoters II+III was lower than that of patients with promoter I (p = 0.006). Multivariate analysis showed that the promoter II+III haplotype was an adverse prognostic marker in HCC. The genetic variants at loci –1053 and +64 of the HTPAP promoter affect the expression of HTPAP, which might be a novel determinant and target for HCC prognosis.

Correlation and prognostic value of osteopontin and Bcl-2 in hepatocellular carcinoma patients after curative resection

Osteopontin (OPN) may facilitate tumorigenesis and metastasis through prevention of tumor cells from apoptosis. Although previous studies have suggested involvement of enhanced Bcl-2 protein family expression, the role of OPN together with Bcl-2 in hepatocellular carcinoma (HCC) remains unknown. In this study, we used western blotting to detect the OPN and Bcl-2 expression levels in cell lines with different OPN backgrounds and HCC tissues, and tumor tissue microarrays to examine OPN and Bcl-2 expression levels in 454 HCC cases. The Kaplan-Meier method and log-rank test were applied to investigate the predictive values of OPN and Bcl-2 in HCC patients. In vitro assays indicated that OPN expression increased concordantly with increasing metastatic potential in MHCC97-H, MHCC97-L, HepG2 and SMMC-7721 cell lines by western blotting, whereas Bcl-2 expression declined. In addition, Bcl-2 was highly upregulated in OPN knockdown MHCC97-H cell lines. Furthermore, in HCC tissues, it was confirmed that OPN levels were also significantly higher in recurrent tumor tissues compared to non-recurrent tissues by western blotting (p<0.001), whereas the contrary occurred in Bcl-2 (p=0.046). Using immunohistochemistry analysis, patients with higher OPN levels had significantly shorter median survival time and recurrence time compared to the lower ones, although the opposite occurred in Bcl-2 levels. Of note, when OPN and Bcl-2 were combined, we found that the co-index of OPN/Bcl-2 was an independent prognostic factor for both overall survival (p<0.001) and time to recurrence (p<0.001). Our findings demonstrate that OPN/Bcl-2 expression is a promising independent predictor of recurrence and survival in HCC. Additionally, Bcl-2 levels may be regulated by OPN in the HCC microenvironment.

Evaluation of midkine as a diagnostic serum biomarker in hepatocellular carcinoma

PURPOSE

To evaluate the value of serum midkine (MDK) as a diagnostic biomarker in hepatocellular carcinoma, particularly for those with negative alpha-fetoprotein (AFP) and at an early stage.

EXPERIMENTAL DESIGN

MDK expression in tumors was assessed by immunohistochemistry from 105 patients with hepatocellular carcinomas or liver cirrhosis. Serum MDK levels were detected by ELISA in 933 participants including hepatocellular carcinomas and hospital controls from different medical centers. Sensitivities and specificities of serum MDK in diagnosing hepatocellular carcinoma according to AFP level and Barcelona Clinic Liver Cancer (BCLC) stage were analyzed.

RESULTS

MDK levels were significantly elevated in hepatocellular carcinoma tissues as well as serum samples. The sensitivity of serum MDK for hepatocellular carcinoma diagnosis was much higher than that of AFP (86.9% vs. 51.9%) with similar specificities (83.9% vs. 86.3%). Notably, serum MDK had an outstanding performance in distinguishing AFP-negative hepatocellular carcinomas from different controls: In those AFP-negative hepatocellular carcinomas, the sensitivity could reach as high as 89.2%. Moreover, receiver operating characteristic (ROC) curve analysis also showed that serum MDK had a better performance compared with AFP in distinguishing early-stage hepatocellular carcinomas as well as small hepatocellular carcinomas. Even in very early-stage hepatocellular carcinomas, MDK showed an obviously higher sensitivity compared with AFP (80% vs. 40%). Furthermore, serum MDK level was significantly decreased in patients with hepatocellular carcinomas after curative resection and re-elevated when tumor relapse occurred.

CONCLUSIONS

Serum MDK is significantly elevated in most hepatocellular carcinomas, including those with negative AFP and at an early stage, which may serve as a novel diagnostic marker in early diagnosis and postoperative monitoring of hepatocellular carcinomas.

MicroRNA-26a suppresses tumor growth and metastasis of human hepatocellular carcinoma by targeting interleukin-6-Stat3 pathway

Down-regulation of microRNA-26a (miR-26a) is associated with poor prognosis of hepatocellular carcinoma (HCC), but its functional mechanism in HCC remains unclear. In this study, we investigated the roles of miR-26a in tumor growth and metastasis of HCC and found that miR-26a was frequently down-regulated in HCC tissues. Down-regulation of miR-26a correlated with HCC recurrence and metastasis. Through gain- and loss-of-function studies, miR-26a was demonstrated to significantly inhibit in vitro cell proliferation, migration, and invasion. In addition, miR-26a induced G1 arrest and promoted apoptosis of HCC cells. Importantly, miR-26a suppressed in vivo tumor growth and metastasis in nude mice models bearing human HCC. Interleukin-6 (IL-6) was identified as a target of miR-26a. Knockdown of IL-6 induced effects on HCC cells similar to those induced by miR-26a. In contrast, IL-6 treatment abrogated the effects induced by miR-26a up-regulation. Moreover, miR-26a dramatically suppressed expression of signal transducer and activator of transcription 3 (Stat3) target genes, including Bcl-2, Mcl-1, cyclin D1, and MMP2. IL-6 treatment antagonized this effect, while knockdown of IL-6 by IL-6 short hairpin RNA (shIL-6) induced inhibitory effects on the expression of p-Stat3 and its main target genes, similar to miR-26a. The messenger RNA and protein levels of IL-6 inversely correlated with miR-26a in HCCs. Patients with high miR-26a or low IL-6 in HCC tissues had a better prognosis with longer overall survival (OS) and time to recurrence (TTR). In multivariate analysis, miR-26a, IL-6, and their combination were demonstrated to be independent prognostic indicators for OS and TTR of HCC patients.

CONCLUSION

miR-26a could suppress tumor growth and metastasis of HCC through IL-6-Stat3 signaling and is a novel prognostic marker and therapeutic target for HCC.

Osteopontin promoter polymorphisms at locus -443 significantly affect the metastasis and prognosis of human hepatocellular carcinoma

Osteopontin (OPN) plays a crucial role in hepatocellular carcinoma (HCC) metastasis. However, little is known about the impact of OPN polymorphisms on cancer progression. In this study, we first identified the single nucleotide polymorphisms (SNPs) in the OPN promoter region by direct sequencing in 30 HCCs, and then evaluated the prognostic values of the selected ones in two large cohorts of 826 HCC patients. The identified SNPs were functionally analyzed using in vitro and in vivo assays and their correlations with OPN levels were also evaluated. Only SNP at locus -443 and their related haplotypes (Ht2: -1748A/-616G/-443T/-155* [*indicates base deletion]; Ht3: -1748A/-616G/-443C/-155*) were significantly associated with overall survival (OS) and time to recurrence (TTR). The patients with the -443TT/TC genotype or Ht2 had a shorter OS and TTR compared with those with -443CC genotype or Ht3. This was further confirmed in the validation cohort. Moreover, this correlation remained significant in patients with small HCCs (≤5 cm). Multivariate analyses indicated that the prognostic performance of the -443 genotypes (OS, P=0.031; TTR, P=0.005) and their related haplotypes (OS, P=0.002; TTR, P=0.001) was independent of other clinicopathological factors. The Ht2 and -443TT genotype could significantly increase the promoter transcriptional activity and expression level of OPN compared with the Ht3 or -443CC genotype, and lead to an obvious increase in both in vitro invasion and in vivo tumor growth and lung metastasis of HCC cells (P<0.05).

CONCLUSION

The genetic variation at locus -443 of the OPN promoter plays important roles in the regulation of OPN expression and cancer progression of HCCs, which is a novel determinant and target for HCC metastasis and prognosis.

Mesenchymal stem cells seldomly fuse with hepatocellular carcinoma cells and are mainly distributed in the tumor stroma in mouse models

Mesenchymal stem cells (MSCs) can have an effect on the growth and metastasis of human malignancies, including hepatocellular carcinoma (HCC); however, their mechanisms of action are not yet fully understood. The cell fusion of stem cell derived from bone marrow with other cells has been increasingly emphasized. The purpose of this study was to investigate the distribution of MSCs in mouse models of HCC, as well as the cell fusion between MSCs and HCC cells. We labeled HCC cells and MSCs with green fluorescence protein (GFP), red fluorescence protein (RFP), 4',6-diamidino-2-phenylindole (DAPI) and 5-bromo-2'-deoxyuridine (BrdU). We found that MSCs fused with HCC cells at a low frequency in vitro. MSCs were found to be merged into HCC tissues after intravenous injection, and compared with the mice not injected with MSCs, the MSCs were mainly distributed in the tumor stroma; Following the injection of the MSCs, the tumor stroma was found to have expanded in size, and the rate of pulmonary metastasis in the MSC-injected group was significantly lower (20%) compared to that in the group not injected with MSCs (100%, P=0.01). These data suggest that cell fusion between MSCs and HCC after engraftment is not one of the main mechanisms of action of the MSCs, while stromal differentiation is a major mechanism of action of the MSCs, leading to the inhibition of the pulmonary metastasis of HCC.

MicroRNA-29a-5p is a novel predictor for early recurrence of hepatitis B virus-related hepatocellular carcinoma after surgical resection

It is still difficult to predict the probability of tumor recurrence after resection of hepatocellular carcinoma (HCC). In this study, we set out to identify specific microRNA (miRNA) in microdissected hepatitis B virus (HBV)-related HCC tissue from formalin-fixed paraffin-embedded (FFPE) samples which might be used in predicting early recurrence after HCC resection. Taqman low density arrays were used to detect the 667 miRNA profiles in both the microdissected tumorous and adjacent non-tumorous liver tissues from 20 HCC patients (discovery set) including 10 patients with early tumor recurrence and 10 without early tumor recurrence and to identify the differentially expressed miRNAs related to HCC recurrence. Then quantitative real-time PCR (qRT-PCR) was used to verify the findings in 106 patients (training set), and to develop a predictive assay. The identified miRNAs were further validated in an independent cohort of 112 patients (validation set). Thirty seven miRNAs were identified from 20 HCC patients and validated in 106 HCC patients using qRT-PCR. A significant association was found between miR-29a-5p level in HCC tissues and early tumor recurrence (P = 0.0002). This association was further confirmed in the independent validation set of 112 patients (P = 0.0154). MiR-29a-5p level was significantly associated with both time to tumor recurrence (TTR) (P = 0.0015) and overall survival (OS) (P = 0.0079) in validation set. In the multivariate analyses, miR-29a-5p was identified as an independent factor for TTR, particularly for those patients with early stage of HCC. The sensitivity and specificity of miR-29a-5p for the prediction of early HCC recurrence of BCLC 0/A stage HCC were 74.2% and 68.2%, respectively. These suggest that miR-29a-5p might be a useful marker for the prediction of early tumor recurrence after HCC resection, especially in BCLC 0/A stage HCCs.

Postoperative serum osteopontin level is a novel monitor for treatment response and tumor recurrence after resection of hepatitis B-related hepatocellular carcinoma

BACKGROUND

Presurgery serum osteopontin (OPN) level has been demonstrated to correlate to tumor recurrence and survival of hepatocellular carcinoma (HCC) patients. This study investigated the postoperative dynamic changes of serum OPN level and its clinical significance in HCC patients.

METHODS

Presurgery serum OPN levels were measured by enzyme-linked immunosorbent assay in cohort A of 179 HCC patients and were compared with the multiple controls including different kinds of liver diseases and healthy individuals. In cohort B of 110 patients with resectable HCCs, besides preoperative assays, serum OPN was monitored at 1 week, 1, and ≥2 months after operation.

RESULTS

The baseline presurgery serum OPN of HCC patients was significantly higher than that of the patients with the other kinds of liver diseases (p < 0.0001). The prognostic values of presurgery serum OPN level in HCC patients were further confirmed. The postsurgery OPN levels were significantly elevated within 1 week after HCC resection, then decreased at 1 month and reached the nadir later than 2 months after operations. It increased again at the time of tumor recurrence, then declined after the second removal of recurrent HCCs. Moreover, postoperative OPN in α-fetoprotein-negative and -positive HCC patients had the same changing pattern; it only correlated to liver function and C-reactive protein level.

CONCLUSIONS

After a transient fluctuation, serum OPN levels significantly decrease after curative resection of HCCs. Postoperative serum OPN could serve as a surrogate serologic biomarker for monitoring treatment response and tumor recurrence after HCC resection, including α-fetoprotein-negative ones.

microRNA-29a suppresses cell proliferation by targeting SPARC in hepatocellular carcinoma

In the present study, we constructed a lentivirus vector encoding the miR-29a precursor and established two stably infected cell lines, PLC-29a and 97L-29a. The overexpression of miR-29a was confirmed by TaqMan RT-PCR and significantly suppressed the growth of the hepatocellular carcinoma cell lines MHCC-97L and PLC. Dual-luciferase reporter assays indicated that the SPARC mRNA 3'UTR was directly targeted by miR-29a since the mutated 3'UTR was not affected. Silencing SPARC expression by RNAi knockdown resulted in a similar effect as miR-29a overexpression on hepatocellular carcinoma (HCC) cell growth regulation. Anti-miR-29a oligonucleotides (AMOs) upregulated the levels of SPARC in the HCC cells. The phosphorylation of AKT/mTOR downstream of SPARC was inhibited in miR-29a-overexpressing HCC cells. We further examined and compared the expression levels of miR-29a in HCC tissues and the corresponding nearby non-cancerous liver tissues of 110 patients with HCC by qRT-PCR, and significantly lower expression of miR-29a was observed in the tissues affected by HCC. Our findings demonstrate that the expression of miR-29a is important in the regulation of the SPARC-AKT pathway and HCC growth.

Abstract 1058: Mutations in isocitrate dehydrogenase 1 and 2 are associated with DNA hypermethylation in intrahepatic cholangiocarcinomas

Cholangiocarcinomas are rare but aggressive cancers, with an increasing incidence and a dismal 5-year survival rate of less than 5%. Mutations in the genes encoding isocitrate dehydrogenase, IDH1 and IDH2, have been reported in ∼70% of gliomas, ∼20% of myeloid leukemias, ∼56% of chondrosarcomas, and ∼10% of melanomas. We discovered IDH1 and IDH2 mutations in 29 of 305 (9%) intrahepatic cholangiocarcinomas. Tumors with mutations in IDH1 or IDH2 had lower 5-hydroxymethylcytosine and higher 5-methylcytosine levels, as well as increased dimethylation of histone H3K79. Mutations in IDH1 or IDH2 were independently associated with longer time to recurrence of cholangiocarcinoma in multivariate analysis (p = 0.046). We identified 2,267 genes that were significantly hypermethylated in tumors with mutations in IDH1 or IDH2. Hypermethylated CpG sites were significantly enriched in CpG shores and in the 1500 bp upstream of annotated transcription start sites, suggesting a global regulation of transcriptional potential. Gene expression profiling of 7 IDH1/2-mutant and 20 IDH1/2-wildtype tumors revealed increased expression of citric acid cycle and oxidative phosphorylation enzymes, as well as decreased expression of cytoskeleton organization genes. Integrated analyses of DNA methylation and gene expression identified interleukin-6 and several of its downstream targets as candidates for silencing by DNA methylation. Conclusions: Cholangiocarcinomas with mutations in IDH1 or IDH2 represent a molecular subclass with distinct signaling pathway alterations.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1058. doi:1538-7445.AM2012-1058

Association of specific genotypes in metastatic suppressor HTPAP with tumor metastasis and clinical prognosis in hepatocellular carcinoma

The phosphatidic acid phosphatase HTPAP has been defined as a metastatic suppressor of hepatocellular carcinoma (HCC), but little is known about its function or potential applications as a prognostic marker. In this study, we analyzed patterns of HTPAP genetic variation and gene expression in 864 patients who underwent HCC resection, assessing these patterns for correlations to tumor metastasis potential. Focusing on two tagSNPs that were selected (+357G/C and +1838A/G), we found that only the +357G/C genotype was significantly associated with HTPAP mRNA and protein expression levels and the probability of metastasis. In an independent cohort of 665 HCC patients, we determined that the +357G/C genotype was associated with shorter time to recurrence and overall survival. Together, these results indicated that the HTPAP tagSNP +357 GG+GC genotypes may influence HCC metastatic potential and clinical prognosis by down-regulating HTPAP expression. Extending these results, a global expression profiling analysis identified 41 genes including the pro-inflammatory genes IL-8 and TLR2 that were significantly overexpressed in the +357 GG+GC group, as possible coregulated markers with HTPAP. Together, our findings identify an HTPAP genotype and associated gene expression pattern that favors metastasis progression and that could be used to predict tumor metastasis and prognosis in HCC patients.

Thrombin is a therapeutic target for metastatic osteopontin-positive hepatocellular carcinoma

We previously identified osteopontin (OPN) as a promoter and thus a potential therapeutic target for hepatocellular carcinoma (HCC) metastasis. The serine protease thrombin interacts with OPN and can modify its biological activity. To explore the role of thrombin alone or in conjunction with OPN in HCC, we studied the correlation of thrombin levels to HCC prognosis in patients with various OPN levels, and evaluated the effects of OPN fragments generated by thrombin cleavage on proliferation and adhesion of HCC cells. We found that the thrombin level was strongly associated with the metastatic potential of HCC cell lines, and that thrombin was remarkably overexpressed in HCC tissue compared with adjacent nontumor tissue. In addition, HCC tissue from patients with recurrent disease displayed much higher thrombin levels, particularly in those with elevated OPN levels. Only HCCs with elevated OPN levels had a significant correlation between high thrombin levels and overall survival (OS; P < 0.01), or time to recurrence (TTR; P < 0.0001) of HCC. Multivariate analysis revealed that thrombin was an independent prognostic indicator. In vitro assays demonstrated that thrombin promotes the proliferation and adhesion of OPN+ HCC cells. Furthermore, thrombin activated the focal adhesion kinase (FAK) pathway of OPN+ HCC cells, which was blocked by the inhibition of integrin β1.

CONCLUSION

Thrombin plays an important role in OPN-mediated aggressive phenotype of HCC through activation of integrin β1-FAK signaling, and is an independent poor prognostic factor for HCC. Thus, thrombin may be a potential therapeutic target to inhibit HCC metastasis in OPN+ patients.

Human mesenchymal stem cells inhibit metastasis of a hepatocellular carcinoma model using the MHCC97-H cell line

The effects of mesenchymal stem cells (MSC) on the growth and metastasis of human malignancies including hepatocellular carcinoma (HCC) are controversial, and the underlying mechanisms are not yet understood. The aim of this study was to explore the role of MSC in the progression of HCC. We investigated the effect of MSC on in vitro proliferation and invasion and in vivo tumor growth and pulmonary metastasis of MHCC97-H HCC cells with a high metastatic potential. The mRNA and protein levels of transforming growth factor-beta 1 (TGFβ1) and MMP, and their association with the effects of MSC on HCC cells were also evaluated. Co-culture of MHCC97-H cells with MSC conditioned medium significantly enhanced in vitro proliferation but inhibited invasiveness. Following MSC treatment of a nude mouse model bearing human HCC, the MSC were predominantly located in the HCC tissues. Compared with controls, MSC-treated mice exhibited significantly larger tumors (3080.51 ± 1234.78 mm(3) vs 2223.75 ± 1000.60 mm(3), P = 0.045), but decreased cellular numbers of lung metastases (49.75 ± 18.86 vs 227.22 ± 74.67, P = 0.046). Expression of TGFβ1 and MMP-2 was significantly downregulated in the MSC-treated HCC cells. TGFβ siRNA concurrently downregulated expression of TGFβ and MMP-2 in HCC cells and blocked the MSC-induced proliferation and invasiveness of MHCC97-H cells. The MSC enhanced tumor growth but significantly inhibited the invasiveness and metastasis of HCC, possibly through downregulation of TGFβ1. These findings suggest that MSC could be useful in controlling metastatic recurrence of HCC.

Abstract A16: Thrombin promotes hepatocellular carcinoma metastasis via mediating osteopontin-dependent tumor growth and adhesion activity

In our previous study, osteopontin (OPN) was identified as one of the leading genes that promote the metastasis of hepatocellular carcinoma (HCC), and a potential therapeutic target for HCC metastasis. The serine protease thrombin can interact with OPN and modify its biologic activity. To explore the role of thrombin alone or collaborating with OPN in HCC, we investigated the thrombin level and its correlation to the prognosis of 72 HCCs with different OPN backgrounds using real-time PCR and Western blot, and evaluated the effects of OPN fragments formed by thrombin cleavage on in vitro proliferation and adhesion of HCC cells. We found that the expression level of thrombin was positively related to the metastatic potentials of HCC cell lines, and was remarkably overexpressed in HCCs compared with the adjacent nontumor tissues. In addition, HCC tissues from patients with recurrent disease displayed much higher thrombin levels, particularly in those with OPN overexpressed. In the immunohistochemical study of 230 HCCs, only in those with a higher OPN level, a significant association was found between the higher thrombin level and the overall survival (OS; P &lt; 0.01) and time to recurrence (TTR; P &lt; 0.0001) of patients. Assays in vitro demonstrated that thrombin could promote the proliferation and adhesion of OPN+ HCC cells. And N-terminal of OPN showed better effects on the proliferation and adhesion abilities of HCC cells than the intact protein. Thrombin treatment could activate FAK pathway of OPN+ HCC cells, and this activation was blocked by the inhibition of integrin β1. Conclusions: Thrombin plays an important role in OPN-mediated aggressive phenotype and poor prognosis of HCC, which may be through the activation of the integrin β1 -FAK signaling. So, thrombin might be a potential therapeutic target to combat HCC progression in thrombin+/OPN+ patients.

Citation Information: Clin Cancer Res 2010;16(14 Suppl):A16.

Expression and prognostic significance of osteopontin and caspase-3 in hepatocellular carcinoma patients after curative resection

Osteopontin (OPN) plays an important role in the development, invasion, and metastasis of malignancies. Recently, several studies have reported that OPN enhances chemoresistance in small-cell lung cancer and breast cancer by blocking caspase-9 and caspase-3-dependent cell apoptosis. The aim of this study was to assess the value of OPN and caspase-3 for predicting tumor recurrence after curative resection in hepatocellular carcinoma (HCC) patients. We found that OPN expression increased concordantly with increasing metastatic potential in human HCC cell lines, whereas caspase-3 expression declined. In a tumor tissue microarray immunohistochemical analysis, we found that patients with higher levels of OPN and lower levels of caspase-3 had a significantly poorer prognosis than patients with lower OPN and higher caspase-3 levels. The combination of OPN and caspase-3 expression thus served as an effective prognosticator. These findings suggest that OPN alone or in combination with caspase-3 may act as an independent indicator for HCC patients after curative resection.

Suitable reference genes for real-time PCR in human HBV-related hepatocellular carcinoma with different clinical prognoses

Background

Housekeeping genes are routinely used as endogenous references to account for experimental differences in gene expression assays. However, recent reports show that they could be de-regulated in different diseases, model animals, or even under varied experimental conditions, which may lead to unreliable results and consequently misinterpretations. This study focused on the selection of suitable reference genes for quantitative PCR in human hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) with different clinical outcomes.

Methods

We evaluated 6 commonly used housekeeping genes' expression levels in 108 HBV-related HCCs' matched tumor and non-tomor tissue samples with different clinical outcomes and 26 normal liver specimens by real-time PCR. The expression stability of the 6 genes was compared using the software programs geNorm and NormFinder. To show the impact of reference genes on data analysis, we took PGK1 as a target gene normalized by each reference gene, and performed one-way ANOVA and the equivalence test.

Results

With the geNorm and NormFinder software programs, analysis of TBP and HPRT1 showed the best stability in all tissue samples, while 18s and ACTB were less stable. When 18s or ACTB was used for normalization, no significant difference of PGK1 expression (p > 0.05) was found among HCC tissues with and without metastasis, and normal liver specimens; however, dramatically differences (p < 0.001) were observed when either TBP or the combination of TBP and HPRT1 were selected as reference genes.

Conclusion

TBP and HPRT1 are the most reliable reference genes for q-PCR normalization in HBV-related HCC specimens. However, the well-used ACTB and 18S are not suitable, which actually lead to the misinterpretation of the results in gene expression analysis.

Lentiviral-mediated miRNA against osteopontin suppresses tumor growth and metastasis of human hepatocellular carcinoma

In our previous study, osteopontin (OPN) was identified as one of the leading genes that promote the metastasis of hepatocellular carcinoma (HCC). However, the mechanism by which OPN promotes metastasis of HCC is not understood. In this study, RNA interference mediated by viral vectors-which could induce a long-lasting down-regulation in gene expression-was applied to analyze the role of OPN in metastasis of HCC. Three lentiviral vectors encoding microRNA against OPN, Lenti.OPNi-1, Lenti.OPNi-2, and Lenti.OPNi-3, were constructed and found to down-regulate the OPN level by 62%, 78%, and 95%, respectively, in HCCLM3 cells which had an overexpression of OPN and a higher metastatic potential. Consequently, both Lenti.OPNi-2 and Lenti.OPNi-3 induced a significant decrease in matrix metalloproteinase (MMP)-2 and urokinase plasminogen activator expression, and led to an obvious inhibition of both in vitro invasion and in vivo lung metastasis of HCCLM3 cells (P < 0.001). Moreover, Lenti.OPNi-3, rather than Lenti.OPNi-2, could also suppress in vitro proliferation and in vivo tumor growth of HCCLM3. Smaller detectable tumors were found in only 50% of mice after implantation of Lenti.OPNi-3-transfected HCCLM3 cells (341 +/- 502.6 mm(3) versus >3500 mm(3) in controls; P < 0.001). Lenti.OPNi-3, not Lenti.OPNi-2, significantly suppressed the MEK/ERK1/2 pathway in HCCLM3 cells. Recombinant OPN was found to induce translocation of p65 into the nucleus of HCC cells and activation of MMP-2 and MEK/ERK/1/2, which were suppressed by the nuclear factor kappaB (NF-kappaB) inhibitor pyrrolidine dithiocarbamate.

CONCLUSION

OPN plays an important role in metastasis as well as tumor growth of HCC, in which different minimum threshold levels of OPN are needed. These effects may occur through activation of the mitogen-activated protein kinase and NF-kappaB pathways, and MMP-2. OPN could be a hopeful target for the control of HCC.