Wilms' tumor 1 gene expression in hepatocellular carcinoma promotes cell dedifferentiation and resistance to chemotherapy

Loss of liver function in chronic liver disease: An identity crisis

Adult hepatocyte identity is constructed throughout embryonic development and fine-tuned after birth. A multinodular network of transcription factors, along with pre-mRNA splicing regulators, define the transcriptome, which encodes the proteins needed to perform the complex metabolic and secretory functions of the mature liver. Transient hepatocellular dedifferentiation can occur as part of the regenerative mechanisms triggered in response to acute liver injury. However, persistent downregulation of key identity genes is now accepted as a strong determinant of organ dysfunction in chronic liver disease, a major global health burden. Therefore, the identification of core transcription factors and splicing regulators that preserve hepatocellular phenotype, and a thorough understanding of how these networks become disrupted in diseased hepatocytes, is of high clinical relevance. In this context, we review the key players in liver differentiation and discuss in detail critical factors, such as HNF4α, whose impairment mediates the breakdown of liver function. Moreover, we present compelling experimental evidence demonstrating that restoration of core transcription factor expression in a chronically injured liver can reset hepatocellular identity, improve function and ameliorate structural abnormalities. The possibility of correcting the phenotype of severely damaged and malfunctional livers may reveal new therapeutic opportunities for individuals with cirrhosis and advanced liver disease.

Biomarker Expression Profiling in Cervix Carcinoma Biopsies Unravels WT1 as a Target of Artesunate

BACKGROUND/AIM

Artemisinin and its derivatives are not only approved antimalarial drugs but also exert strong anticancer activity. Based on the clinical activity of artesunate (ART) that has been previously reported in cervix carcinoma, we investigated a panel of 12 different biomarkers and identified the Wilms Tumor 1 (WT1) protein as a potential target of ART.

PATIENTS AND METHODS

Matched biopsies of cervical carcinoma before, during, and after therapy from patients treated with ART were investigated for induction of apoptosis (TUNEL assay) and expression of Wilms Tumor protein 1 (WT1), 14-3-3 ζ, cluster of differentiation markers (CD4, CD8, CD56), ATP-binding cassette transporter B5 (ABCB5), glutathione S-transferase P1 (GSTP1), inducible nitric oxide synthase (iNOS), translationally controlled tumor protein (TCTP), eukaryotic elongation factor 3 (eIF3), and ADP/ATP translocase by immunohistochemistry. WT1 has been selected for more detailed analyses using molecular docking in silico, microscale thermophoresis using recombinant WT1, and cytotoxicity testing (resazurin assay) using HEK293 cells transfected with four different WT1 splice variants.

RESULTS

The fraction of apoptotic cells and the expression of WT1, 14-3-3 ζ, and CD4 increased upon ART treatment in tumors of patients. ART was bound in silico to a domain located at the DNA-binding site of WT1, while dihydroartemisinin (DHA) was bound with low affinity to a different site of WT1 not related to DNA-binding. The results were verified using microscale thermophoresis, where ART but not DHA bound to recombinant WT1. Transfectants overexpressing different WT1 splice variants exerted low but significant resistance to ART (≈2-fold).

CONCLUSION

WT1 may represent a novel target of ART in cancer cells that contribute to the response of tumor cells to this drug.

Application of Bioinformatics Analysis to Identify Important Pathways and Hub Genes in Ovarian Cancer Affected by WT1

Wilms tumor gene (WT1) is used as a marker for the diagnosis and prognosis of ovarian cancer. However, the molecular mechanisms involving WT1 in ovarian cancer require further study. Herein, we used bioinformatics and other methods to identify important pathways and hub genes in ovarian cancer affected by WT1. The results showed that WT1 is highly expressed in ovarian cancer and is closely related to the overall survival and progression-free survival (PFS) of ovarian cancer. In ovarian cancer cell line SKOV3, WT1 downregulation increased the mRNA expression of 638 genes and decreased the mRNA expression of 512 genes, which were enriched in the FoxO, AMPK, and the Hippo signaling pathways. The STRING online tool and Cytoscape software were used to construct a Protein-protein interaction (PPI) network and for Module analysis, and 18 differentially expressed genes (DEGs) were selected. Kaplan-Meier plotter analysis revealed that 16 of 18 genes were related to prognosis. Analysis of GEPIA datasets indicated that 7 of 16 genes were differentially expressed in ovarian cancer tissues and in normal tissues. The expression of IGFBP1 and FBN1 genes increased significantly after WT1 interference, while the expression of the SERPINA1 gene decreased significantly. The correlation between WT1 expression and that of these three genes was consistent with that of ovarian cancer tissues and normal tissues. According to the GeneMANIA online website analysis, there were complex interactions between WT1, IGFBP1, FBN1, SERPINA1, and 20 other genes. In conclusion, we have identified important signaling pathways involving WT1 that affect ovarian cancer, and distinguished three differentially expressed genes regulated by WT1 associated with the prognosis of ovarian cancer. Our findings provide evidence outlining mechanisms involving WT1 gene expression in ovarian cancer and provides a rational for novel treatment of ovarian cancer.

Peptide-Based Vaccines for Hepatocellular Carcinoma: A Review of Recent Advances

Primary liver cancer is the sixth most commonly diagnosed cancer and the third leading cause of cancer-related deaths worldwide. After surgery, up to 70% of patients experience relapses. The current first-line therapy for advanced cases of hepatocellular carcinoma (HCC) comprises sorafenib and lenvatinib administered as single-drug therapies. Regorafenib, cabozantinib, and ramucirumab are administered as second-line therapies. Recently, it has been reported that using the immune checkpoint inhibitors atezolizumab (anti-PDL1 antibody) and bevacizumab (anti-VEGF antibody) leads to longer overall survival of unresectable cases, when compared with the use of sorafenib. The role of cancer immunity against HCC has attracted the attention of clinicians. In this review, we describe our phase I/II clinical trials of peptide vaccines targeting GPC3 in HCC and discuss the potential of peptide vaccines targeting common cancer antigens that are highly expressed in HCC, such as WT-I, AFP, ROBO1, and FOXM1. Further, we introduce recent cancer vaccines targeting neoantigens, which have attracted attention in recent times, as well as present our preclinical studies, the results of which might aid to initiate a neoantigen vaccine clinical trial, which would be the first of its kind in Japan.

The splicing regulator SLU7 is required to preserve DNMT1 protein stability and DNA methylation

Gene expression is finely and dynamically controlled through the tightly coordinated and interconnected activity of epigenetic modulators, transcription and splicing factors and post-translational modifiers. We have recently identified the splicing factor SLU7 as essential for maintaining liver cell identity and genome integrity and for securing cell division both trough transcriptional and splicing mechanisms. Now we uncover a new function of SLU7 controlling gene expression at the epigenetic level. We show that SLU7 is required to secure DNMT1 protein stability and a correct DNA methylation. We demonstrate that SLU7 is part in the chromatome of the protein complex implicated in DNA methylation maintenance interacting with and controlling the integrity of DNMT1, its adaptor protein UHRF1 and the histone methyl-transferase G9a at the chromatin level. Mechanistically, we found that SLU7 assures DNMT1 stability preventing its acetylation and degradation by facilitating its interaction with HDAC1 and the desubiquitinase USP7. Importantly, we demonstrate that this DNMT1 dependency on SLU7 occurs in a large panel of proliferating cell lines of different origins and in in vivo models of liver proliferation. Overall, our results uncover a novel and non-redundant role of SLU7 in DNA methylation and present SLU7 as a holistic regulator of gene expression.

Novel WT1 Target Genes: IL-2, IL-2RB, and IL-2RG Discovered during WT1 Silencing Using Lentiviral-Based RNAi in Myeloid Leukemia Cells

Wilms' tumor 1 (WT1) is a transcription factor which plays a major role in cell proliferation, differentiation, survival, and apoptosis. WT1 was first identified as a tumor suppressor gene in Wilms' tumor. However, overexpression of WT1 has been detected in several types of malignancy including some types of leukemia. To investigate the molecular mechanism underlying WT1-mediated leukemogenesis, lentiviral-based siRNA was employed as a tool to suppress WT1 expression in the myeloid leukemia cell line, K562. Successfully, both WT1 RNA and protein levels were downregulated in the leukemia cells. The silencing of WT1 resulted in significant growth inhibition in WT1-siRNA-treated cells for 40 ± 7.0%, 44 ± 9.5%, and 88 ± 9.1% at 48, 72, and 96 hours posttransduction as compared with the control cells, respectively. By using apoptosis detection assays (caspase-3/7 activity and Annexin V-FITC/PI assays), WT1 silencing induced a higher degree of early and late apoptosis in siRNA-treated K562 as compared with the control cells. Interestingly, the expression of survival signaling genes, IL-2, IL-2RB, and IL-2RG, was also suppressed after WT1-siRNA treatment. In addition, the WT1 silencing also inhibited the S phase of the cell cycle and induced cell death. Our results indicated that WT1 silencing by siRNA can suppress cellular proliferation, induce apoptosis, and reduce S phase fraction of K562 cells. Moreover, transcriptional modulation of IL-2, IL-2RB, and IL2-2RG expression by WT1 was likely involved in this phenotypic change. Overall, this study confirmed the oncogenic role of WT1 in myeloid leukemia and discovered the new target genes of WT1 which are likely involved in WT1-mediated leukemogenesis.

Control of Cell Identity by the Nuclear Receptor HNF4 in Organ Pathophysiology

Hepatocyte Nuclear Factor 4 (HNF4) is a transcription factor (TF) belonging to the nuclear receptor family whose expression and activities are restricted to a limited number of organs including the liver and gastrointestinal tract. In this review, we present robust evidence pointing to HNF4 as a master regulator of cellular differentiation during development and a safekeeper of acquired cell identity in adult organs. Importantly, we discuss that transient loss of HNF4 may represent a protective mechanism upon acute organ injury, while prolonged impairment of HNF4 activities could contribute to organ dysfunction. In this context, we describe in detail mechanisms involved in the pathophysiological control of cell identity by HNF4, including how HNF4 works as part of cell-specific TF networks and how its expression/activities are disrupted in injured organs.

Wilms tumor 1 regulates lipid accumulation in human endometrial stromal cells during decidualization

We previously reported that the transcription factor Wilms tumor 1 (WT1) regulates the expression of insulin-like growth factor-binding protein-1 (IGFBP-1) and prolactin (PRL) during decidualization of human endometrial stromal cells (ESCs). However, other roles of WT1 in decidualization remain to be fully clarified. Here, we investigated how WT1 regulates the physiological functions of human ESCs during decidualization. We incubated ESCs isolated from proliferative-phase endometrium with cAMP to induce decidualization, knocked down WT1 with siRNA, and generated three types of treatments (nontreated cells, cAMP-treated cells, and cAMP-treated + WT1-knockdown cells). To identify WT1-regulated genes, we used gene microarrays and compared the transcriptome data obtained among these three treatments. We observed that WT1 up-regulates 121 genes during decidualization, including several genes involved in lipid transport. The WT1 knockdown inhibited lipid accumulation (LA) in the cAMP-induced ESCs. To examine the mechanisms by which WT1 regulates LA, we focused on very low-density lipoprotein receptor (VLDLR), which is involved in lipoprotein uptake. We found that cAMP up-regulates VLDLR and that the WT1 knockdown inhibits it. Results of ChIP assays revealed that cAMP increases the recruitment of WT1 to the promoter region of the VLDLR gene, indicating that WT1 regulates VLDLR expression. Moreover, VLDLR knockdown inhibited cAMP-induced LA, and VLDLR overexpression reverted the suppression of LA caused by the WT1 knockdown. Taken together, our results indicate that WT1 enhances lipid storage by up-regulating VLDLR expression in human ESCs during decidualization.

Splicing events in the control of genome integrity: role of SLU7 and truncated SRSF3 proteins

Genome instability is related to disease development and carcinogenesis. DNA lesions are caused by genotoxic compounds but also by the dysregulation of fundamental processes like transcription, DNA replication and mitosis. Recent evidence indicates that impaired expression of RNA-binding proteins results in mitotic aberrations and the formation of transcription-associated RNA-DNA hybrids (R-loops), events strongly associated with DNA injury. We identify the splicing regulator SLU7 as a key mediator of genome stability. SLU7 knockdown results in R-loops formation, DNA damage, cell-cycle arrest and severe mitotic derangements with loss of sister chromatid cohesion (SCC). We define a molecular pathway through which SLU7 keeps in check the generation of truncated forms of the splicing factor SRSF3 (SRp20) (SRSF3-TR). Behaving as dominant negative, or by gain-of-function, SRSF3-TR impair the correct splicing and expression of the splicing regulator SRSF1 (ASF/SF2) and the crucial SCC protein sororin. This unique function of SLU7 was found in cancer cells of different tissue origin and also in the normal mouse liver, demonstrating a conserved and fundamental role of SLU7 in the preservation of genome integrity. Therefore, the dowregulation of SLU7 and the alterations of this pathway that we observe in the cirrhotic liver could be involved in the process of hepatocarcinogenesis.

EGR-mediated control of STIM expression and function

Ca²⁺ is a ubiquitous, dynamic and pluripotent second messenger with highly context-dependent roles in complex cellular processes such as differentiation, proliferation, and cell death. These Ca²⁺ signals are generated by Ca²⁺-permeable channels located on the plasma membrane (PM) and endoplasmic reticulum (ER) and shaped by PM- and ER-localized pumps and transporters. Differences in the expression of these Ca²⁺ homeostasis proteins contribute to cell and context-dependent differences in the spatiotemporal organization of Ca²⁺ signals and, ultimately, cell fate. This review focuses on the Early Growth Response (EGR) family of zinc finger transcription factors and their role in the transcriptional regulation of Stromal Interaction Molecule (STIM1), a critical regulator of Ca²⁺ entry in both excitable and non-excitable cells.

Aberrant expression of alternative isoforms of transcription factors in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most prevalent malignancies worldwide and the second leading cause of death among all cancer types. Deregulation of the networks of tissue-specific transcription factors (TFs) observed in HCC leads to profound changes in the hepatic transcriptional program that facilitates tumor progression. In addition, recent reports suggest that substantial aberrations in the production of TF isoforms occur in HCC. In vitro experiments have identified distinct isoform-specific regulatory functions and related biological effects of liver-specific TFs that are implicated in carcinogenesis, which may be relevant for tumor progression and clinical outcome. This study reviews available data on the expression of isoforms of liver-specific and ubiquitous TFs in the liver and HCC and their effects, including HNF4α, C/EBPs, p73 and TCF7L2, and indicates that assessment of the ratio of isoforms and targeting specific TF variants may be beneficial for the prognosis and treatment of HCC.

Long non-coding RNAs as biomarkers and therapeutic targets: Recent insights into hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most prevalent primary liver cancer worldwide, and the survival rates of patients with HCC remains quite low after 5years. Long non-coding RNAs (LncRNAs) are a novel class of non-coding RNAs that are capable of regulating gene expression at various levels. Recent works have demonstrated that lncRNAs are often dysregulated in HCC, and the dysregulation of some of these lncRNAs are associated with the clinicopathological features of HCC. They regulate cell proliferation, apoptosis, autophagy, Epithelial-Mesenchymal Transition (EMT), invasion and metastasis of HCC by modulating gene expression and cancer-related signaling pathways, and thus contribute to the onset and progression of HCC. In this review, we provide a comprehensive survey of dysregulated lncRNAs in HCC, with particular focus on the functions and regulatory mechanisms of several essential and important lncRNAs, and discuss their potential clinical application as early diagnostic and/or prognostic biomarkers or therapeutic targets for HCC.

Aberrant methylation of tumour suppressor genes WT1, GATA5 and PAX5 in hepatocellular carcinoma

BACKGROUND

Aberrant hypermethylation of tumour suppressor genes (TSGs) occurring in hepatocellular carcinoma (HCC) could provide a mean of molecular characterisation of this cancer. The aim of this study was to investigate promoter methylation and gene expression of selected TSGs in HCC to identify candidate genes for further validation as potential biomarkers.

METHODS

Methylation-specific multiplex ligation-dependent probe amplification method was used to measure the methylation status of 25 TSGs in 49 HCC samples and 36 corresponding non-cancerous liver tissue samples. Relative expression of the differentially methylated genes was assessed at the mRNA level using quantitative PCR.

RESULTS

We observed a significantly higher methylation in genes WT1, PAX5, PAX6, PYCARD and GATA5 in HCC compared with control samples. The expression of PAX5 was significantly decreased by methylation; conversely methylation of WT1 was associated with higher mRNA levels. Methylation of GATA5 was significantly associated with overall survival and methylation of WT1 and PAX5 significantly varied between patients with ALBI score 1 vs. 2+3. Moreover, PAX5 was significantly more methylated in patients with tumour grade 2+3 vs. grade 1, and methylation of the PAX5 correlated with the patient's age at the time of diagnosis.

CONCLUSIONS

HCC evince aberrant promoter methylation of WT1, PAX5, PAX6, PYCARD and GATA5 genes. Correlation between GATA5, WT1 and PAX5 methylation and clinical/histological parameters is suggestive of applicability of these markers in non-invasive (epi)genetic testing in HCC.

Regulation of hepatic microRNA expression by hepatocyte nuclear factor 4 alpha

AIM

To uncover the role of hepatocyte nuclear factor 4 alpha (HNF4α) in regulating hepatic expression of microRNAs.

METHODS

Microarray and real-time PCR were used to determine hepatic expression of microRNAs in young-adult mice lacking Hnf4α expression in liver (Hnf4α-LivKO). Integrative genomics viewer software was used to analyze the public chromatin immunoprecipitation-sequencing datasets for DNA-binding of HNF4α, RNA polymerase-II, and histone modifications to loci of microRNAs in mouse liver and human hepatoma cells. Dual-luciferase reporter assay was conducted to determine effects of HNF4α on the promoters of mouse and human microRNAs as well as effects of microRNAs on the untranslated regions (3’UTR) of two genes in human hepatoma cells.

RESULTS

Microarray data indicated that most microRNAs remained unaltered by Hnf4α deficiency in Hnf4α-LivKO mice. However, certain liver-predominant microRNAs were down-regulated similarly in young-adult male and female Hnf4α-LivKO mice. The down-regulation of miR-101, miR-192, miR-193a, miR-194, miR-215, miR-802, and miR-122 as well as induction of miR-34 and miR-29 in male Hnf4α-LivKO mice were confirmed by real-time PCR. Analysis of public chromatin immunoprecipitation-sequencing data indicates that HNF4α directly binds to the promoters of miR-101, miR-122, miR-194-2/miR-192 and miR-193, which is associated with histone marks of active transcription. Luciferase reporter assay showed that HNF4α markedly activated the promoters of mouse and human miR-101b/miR-101-2 and the miR-194/miR-192 cluster. Additionally, miR-192 and miR-194 significantly decreased activities of luciferase reporters for the 3’UTR of histone H3F3 and chromodomain helicase DNA binding protein 1 (CHD1), respectively, suggesting that miR-192 and miR-194 might be important in chromosome remodeling through directly targeting H3F3 and CHD1.

CONCLUSION

HNF4α is essential for hepatic basal expression of a group of liver-enriched microRNAs, including miR-101, miR-192, miR-193a, miR-194 and miR-802, through which HNF4α may play a major role in the post-transcriptional regulation of gene expression and maintenance of the epigenome in liver.

Safety and immunogenicity of neoadjuvant treatment using WT1-immunotherapeutic in combination with standard therapy in patients with WT1-positive Stage II/III breast cancer: a randomized Phase I study

Purpose

This Phase I, multicenter, randomized study (ClinicalTrials.gov NCT01220128) evaluated the safety and immunogenicity of recombinant Wilms’ tumor 1 (WT1) protein combined with the immunostimulant AS15 (WT1-immunotherapeutic) as neoadjuvant therapy administered concurrently with standard treatments in WT1-positive breast cancer patients.

Methods

Patients were treated in 4 cohorts according to neoadjuvant treatment (A: post-menopausal, hormone receptor [HR]-positive patients receiving aromatase inhibitors; B: patients receiving chemotherapy; C: HER2-overexpressing patients on trastuzumab–chemotherapy combination; D: HR-positive/HER2-negative patients on chemotherapy). Patients (cohorts A–C) were randomized (2:1) to receive 6 or 8 doses of WT1-immunotherapeutic or placebo together with standard neoadjuvant treatment in a double-blind manner; cohort D patients received WT1-immunotherapeutic in an open manner. Safety was assessed throughout the study. WT1-specific antibodies were assessed pre- and post-vaccination.

Results

Sixty-two patients were randomized; 60 received ≥ one dose of WT1-immunotherapeutic. Two severe toxicities were reported: diarrhea (cohort C; also reported as a grade 3 serious adverse event) and decreased left ventricular ejection fraction (cohort B; also reported as a grade 2 adverse event). Post-dose 4 of WT1-immunotherapeutic, 10/10 patients from cohort A, 0/8 patients from cohort B, 6/11 patients from cohort C, and 2/3 patients from cohort D were humoral responders. The sponsor elected to close the trial prematurely.

Conclusions

Concurrent administration of WT1-immunotherapeutic and standard neoadjuvant therapy was well tolerated and induced WT1-specific antibodies in patients receiving neoadjuvant aromatase inhibitors. In patients on neoadjuvant chemotherapy or trastuzumab–chemotherapy combination, the humoral response was impaired or blunted, likely due to either co-administration of corticosteroids and/or the chemotherapies themselves.

Electronic supplementary material

The online version of this article (doi:10.1007/s10549-017-4130-y) contains supplementary material, which is available to authorized users.

A genome-wide association study identifies WT1 variant with better response to 5-fluorouracil, pirarubicin and cyclophosphamide neoadjuvant chemotherapy in breast cancer patients

Breast cancer is believed to result from the interplay of genetic and non-genetic risk factors, and individual genetic variation may influence the efficacy of chemotherapy. Here we conducted a genome-wide association study to identify single nucleotide polymorphisms (SNPs) associated with response to anthracycline- and taxane-based neoadjuvant chemotherapy in breast cancer patients. In the discovery stage, we divided 92 patients who received anthracycline-based neoadjuvant chemotherapy into 2 groups according to pathologic response and performed a genome-wide study using Affymetrix SNP6.0 genechip. Of 389,795 SNPs associated with pathologic complete response (pCR), we identified 2 SNPs, rs6044100 and rs1799937, that were significantly associated with pCR after neoadjuvant chemotherapy. In the validation stage, genotype analysis of samples from an independent cohort of 401 patients who received anthracycline-based neoadjuvant regimens and 467 patients who received taxane-based regimens was performed using sequencing analysis. We found that only SNP rs1799937, located in the WT1 gene, was associated with pCR after anthracycline-based neoadjuvant therapy (AA vs GG; odds ratio [OR], 2.81; 95% confidence interval [CI], 1.13-6.98; P < 0.05) but not after taxane-based neoadjuvant therapy (AA vs GG; OR, 0.85; 95% CI, 0.36-2.04; P = 0.72). These results suggest that WT1 may be a potential target of anthracycline-based neoadjuvant therapy for breast cancer.

Insulin-Like Growth Factor I (IGF-I) Expressed from an AAV1 Vector Leads to a Complete Reversion of Liver Cirrhosis in Rats

IGF-I modulates liver tissue homeostasis. It is produced by hepatocytes and signals within the liver through IGF-I receptor expressed on hepatic stellate cells (HSCs). Liver cirrhosis is characterized by marked IGF-I deficiency. Here we compared the effect of two different gene therapy vectors encoding IGF-I as a potential treatment for cirrhotic patients. Rats with carbon tetrachloride-induced liver cirrhosis were treated with controls or with adeno-associated virus 1 (AAV) or simian virus 40 (SV40) vectors expressing IGF-I (AAVIGF-I or SVIGF-I) and molecular and histological studies were performed at 4 days, 8 weeks and 16 weeks. Increased levels of IGF-I were observed in the liver as soon as 4 days after vector administration. Control cirrhotic rats showed increased hepatic expression of pro-inflammatory and pro-fibrogenic factors including transforming growth factor beta (TGFβ), tumor necrosis factor-alpha (TNFα), connective tissue growth factor (CTGF), and vascular endothelial growth factor (VEGF) together with upregulation of α-smooth muscle actin (αSMA), a marker of HSC activation. In IGF-I-treated rats the levels of all these molecules were similar to those of healthy controls by week 8 post-therapy. Of note, the decline of TGFβ, CTGF, VEGF and αSMA expression was more rapid in AAVIGF-I treated animals reaching statistical significance by day 4 post-therapy. IGF-I-treated rats showed similar improvement of liver function tests in parallel with upregulation of hepatocyte nuclear factor 4α (HNF4α), a factor that promotes hepatocellular differentiation. A significant decrease of liver fibrosis, accompanied by upregulation of the hepatoprotective and anti-fibrogenic hepatocyte growth factor (HGF), occurred in all IGF-I-treated rats but complete reversal of liver cirrhosis took place only in AAVIGF-I group. Therefore, AAVIGF-I reverts liver cirrhosis in rats, a capability which deserves clinical testing.

Targeting of cancer‑associated fibroblasts enhances the efficacy of cancer chemotherapy by regulating the tumor microenvironment

Cancer-associated fibroblasts (CAFs), key components of the tumor stroma, can regulate tumorigenesis by altering the tumor microenvironment in variety of ways to promote angiogenesis, recruit inflammatory immune cells and remodel the extracellular matrix. Using a murine xenograft model of colon carcinoma, the present study observed that oxaliplatin increased the accumulation of CAFs and stimulated the production of cytokines associated with CAFs. When oxaliplatin was combined with the small-molecule dipeptidyl peptidase inhibitor PT-100, which inhibits CAFs by targeting fibroblast activation protein (FAP), the accumulation of CAFs was markedly reduced, xenograft tumor growth was significantly suppressed and the survival of the mice increased, compared to those of mice treated with oxaliplatin or PT-100 alone. Furthermore, the xenograft tumor tissues of mice treated with oxaliplatin and PT-100 contained lower numbers of tumor-associated macrophages and dendritic cells, expressed lower levels of cytokines associated with CAFs and had a lower density of CD31+ endothelial cells. The present study demonstrated that pharmacological inhibition of CAFs improved the response to chemotherapy, reduced the recruitment of immune tumor-promoting cells and inhibited angiogenesis. Combining chemotherapy with agents which target CAFs may represent a novel strategy for improving the efficacy of chemotherapy and reducing chemoresistance.

WT1-AS promotes cell apoptosis in hepatocellular carcinoma through down-regulating of WT1

Background

The antisense of the tumor suppressor gene WT1 (WT1-AS) is a long non-coding RNA. The role of WT1-AS in the development of hepatocellular carcinoma (HCC) has not yet been elucidated.

Methods

Quantitative real-time PCR and western blot analyses were used to measure levels of WT1-AS and its related genes in tumor and corresponding adjacent tumor tissues of HCC patients. The effect on HCC cell proliferation and apoptosis was assessed by EdU incorporation assays and PI-Annexin-V staining, respectively. ShRNA and dual-luciferase assays were used to investigate the regulatory relationship between WT1-AS and WT1 in cell lines.

Results

WT1-AS expression correlated negatively with WT1 expression in HCC tumor tissue. Kaplan-Meier curve analysis revealed that WT1-AS expression is a reliable indicator of HCC prognosis. The downregulation of WT1 expression by WT1-AS promoted cell apoptosis by suppressing the JAK/STAT3 signaling pathway. Bioinformatics analysis showed that WT1-AS downregulates WT1 by binding to the TATA region of the WT1 promotor. WT1-AS was also able to reverse WT1-mediated resistance to Dox based chemotherapy in HCC cells.

Conclusions

WT1-AS downregulates WT1 expression in HCC tumors and promotes apoptosis by binding to the promoter region of WT1. Our findings suggest that WT1-AS may function as a tumor suppressor in HCC by reversing the oncogenic effects of WT1.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-015-0233-7) contains supplementary material, which is available to authorized users.

Regulation of hepatocyte identity and quiescence

The liver is a highly differentiated organ with a central role in metabolism, detoxification and systemic homeostasis. To perform its multiple tasks, liver parenchymal cells, the hepatocytes, express a large complement of enabling genes defining their complex phenotype. This phenotype is progressively acquired during fetal development and needs to be maintained in adulthood to guarantee the individual's survival. Upon injury or loss of functional mass, the liver displays an extraordinary regenerative response, mainly based on the proliferation of hepatocytes which otherwise are long-lived quiescent cells. Increasing observations suggest that loss of hepatocellular differentiation and quiescence underlie liver malfunction in chronic liver disease and pave the way for hepatocellular carcinoma development. Here, we briefly review the essential mechanisms leading to the acquisition of liver maturity. We also identify the key molecular factors involved in the preservation of hepatocellular homeostasis and finally discuss potential strategies to preserve liver identity and function.

Glycyrrhizin, silymarin, and ursodeoxycholic acid regulate a common hepatoprotective pathway in HepG2 cells

BACKGROUND

Glycyrrhizin, silymarin, and ursodeoxycholic acid are widely used hepatoprotectants for the treatment of liver disorders, such as hepatitis C virus infection, primary biliary cirrhosis, and hepatocellular carcinoma.

PURPOSE

The gene expression profiles of HepG2 cells responsive to glycyrrhizin, silymarin, and ursodeoxycholic acid were analyzed in this study.

METHODS

HepG2 cells were treated with 25 µM hepatoprotectants for 24 h. Gene expression profiles of hepatoprotectants-treated cells were analyzed by oligonucleotide microarray in triplicates. Nuclear factor-κB (NF-κB) activities were assessed by luciferase assay.

RESULTS

Among a total of 30,968 genes, 252 genes were commonly regulated by glycyrrhizin, silymarin, and ursodeoxycholic acid. These compounds affected the expression of genes relevant various biological pathways, such as neurotransmission, and glucose and lipid metabolism. Genes involved in hepatocarcinogenesis, apoptosis, and anti-oxidative pathways were differentially regulated by all compounds. Moreover, interaction networks showed that NF-κB might play a central role in the regulation of gene expression. Further analysis revealed that these hepatoprotectants inhibited NF-κB activities in a dose-dependent manner.

CONCLUSION

Our data suggested that glycyrrhizin, silymarin, and ursodeoxycholic acid regulated the expression of genes relevant to apoptosis and oxidative stress in HepG2 cells. Moreover, the regulation by these hepatoprotectants might be relevant to the suppression of NF-κB activities.

Down-regulation of STAT3 expression using vector-based RNA interference promotes apoptosis in Hepatocarcinoma cells

In this study, we followed a DNA vector-based RNAi approach to silence the signal transducer and activator of transcription 3 (STAT3) expression in Bel-7402 cells, to explore how the Janus kinase (JAK)/STAT3 signaling pathway influences the apoptosis of hepatocarcinoma cells. According to GenBank's STAT3 cDNA, the plasmid pGCsi.U6/neoRFP STAT3, which was designed for expression of STAT3 small interfering RNA (siRNA), was constructed and synthesized, and then transfected into Bel-7402 cells using Lipofectamine 2000. Cells with or without siRNA transfection were treated in wells. The apoptotic rate was detected by flow cytometry (FCM) and by staining with the Annexin V/propidium iodide (PI) apoptosis detection kit. Simultaneously, the mitochondrial membrane potential (ΔΨm) was visualized by JC-1 fluorescence staining and observed using the inverted fluorescence microscope. Furthermore, the expression of caspase-3 protein was analyzed by Western blotting. The results showed that treatment with STAT3 siRNA displayed effects in the Bel-7402 cells, causing a significantly increased apoptotic ratio (P < 0.05). The mitochondrial membrane potential of the STAT3 siRNA group, observed by the JC-1 fluorescence staining, decreased significantly. The protein expression of active caspase-3 increased with STAT3 siRNA treatment, and was significantly higher than that of the control group (P < 0.05). STAT3 gene-silencing significantly improves the apoptotic effect against Bel-7402 cells.

Wilms' tumor 1 (WT1) expression and prognosis in solid cancer patients: a systematic review and meta-analysis

Though proposed as a promising target antigen for cancer immunotherapy, the prognostic value of Wilms' tumor 1 (WT1) in solid tumors remains inconclusive. Here, we report a systematic review and meta-analysis of the association between WT1 expression and prognosis in solid tumors. PubMed, Web of Science and Google Scholar were searched to identify studies exploring the impact of WT1 on clinical outcomes, including overall survival (OS), disease-specific survival (DSS), disease-free survival (DFS), relapse/recurrence-free survival (RFS) or progression-free survival (PFS), in solid cancer patients. Hazard ratio (HR) and 95% confidence interval (CI) were applied to assess the strength of these associations. Finally, a total of 29 eligible studies with 4090 patients were identified for qualitative analysis, and 22 studies with 3620 patients were enrolled for quantitative synthesis. Overall, positive expression of WT1 was significantly associated with worse OS (metaHR = 1.48, 95% CI = 1.11–1.97) and DFS/RFS/PFS (metaHR = 2.14, 95% CI = 1.42–3.21). Subgroup analyses showed that WT1 positive expression could independently predict unfavorable DFS/RFS/PFS (metaHR = 1.86, 95%CI = 1.04–3.35). In summary, our study suggests that WT1 may be a potential marker to predict DFS/RFS/PFS in solid tumor patients. Further studies are needed to confirm the role of WT1 expression in clinical practice.

Restitution of gene expression and histone acetylation signatures altered by hepatitis B virus through antiviral microRNA-like molecules in nontransformed murine hepatocytes

BACKGROUND

Virus-host interactions result in altered gene expression profiles in host cell nuclei and enable virus particle production, thus obligatorily involving changes in their epigenomes. Neither such epigenome changes nor their response to antiviral treatment have been extensively studied to date, although viral infections are known to contribute to the long-term development of severe secondary diseases, for example, hepatocellular carcinoma. This may be causally linked to virus-induced persistent plastic chromatin deformations.

RESULTS

We studied whether impaired hepatitis B virus (HBV) replication can lead to the restitution of epigenome signatures hypothesizing that hepatocytes alternatively could adopt a 'memory' state of the infection; that is, the chromatin could persist in a HBV-induced configuration potentially inheritable between dividing hepatocytes. We therefore determined epigenomic signatures and gene expression changes altered by HBV and the effects of suppressed HBV replication in nontransformed hepatocytes of newborn mice. Further we investigated differential histone acetyltransferase and histone deacetylase activities in HBV-negative and HBVpositive hepatocytes, as well as the effects of HBV suppression on gene expression and the chromatin landscape. We show that the expression of several genes and the chromatin landscape become altered upon HBV infection, including global hypoacetylation of H2A.Z and H3K9. Reporter assays monitoring the activities of histone acetyltransferases or histone deacetylases, respectively, suggest that hypoacetylation most probably depends on elevated sirtuin deacetylase activity, but not on class I/II histone deacetylases. Using Micrococcus nuclease to study the chromatin accessibility in met murine-D3 and hepatitis B virus met murine hepatocytes, we demonstrate that the observed differences in H2A.Z/H3K9 acetylation lead to global chromatin structure changes. At all selected sites examined by chromatin immunoprecipitation and quantitative real-time PCR, these effects can be partly restituted via the nucleoside analog reverse transcriptase inhibitor 3TC or using anti-HBV microRNA-like molecules.

CONCLUSIONS

Increased sirtuin activity might lead to global histone hypoacetylation signatures, which could contribute to the HBV-induced pathomechanism in nontransformed hepatocytes. Using several techniques to suppress HBV replication, we observed restituted gene expression and chromatin signature patterns reminiscent of noninfected hepatocytes. Importantly, ectopic expression of antiviral short-hairpin RNA, but not microRNA-like molecules, provoked intolerable off-target effects on the gene expression level.

Wilms' tumor 1 enhances Cisplatin-resistance of advanced NSCLC

Wilms' tumor 1 (WT1) is an oncogene that has been correlated with tumor progression, bad prognosis and chemo-resistance in Non-Small-Cell lung cancer (NSCLC). Here, we found that WT1 expression is significantly higher in NSCLCs than in benign controls, and that Cisplatin-resistant patients display a notable increase in WT1 expression following relapse. In vitro, WT1 levels were associated with the IC50 of NSCLC cells and increased along with treatment time and dose of Cisplatin. Furthermore, WT1 enhanced Major Vault Protein (MVP) transcription via binding to its promoter. Therefore, WT1 may be a potential therapeutic target for solving resistance.

HCA519/TPX2: a potential T-cell tumor-associated antigen for human hepatocellular carcinoma

Background

Immunotherapy for human hepatocellular cancer (HCC) is slowly making progress towards treating these fatal cancers. The identification of new antigens can improve this approach. We describe a possible new antigen, hepatocellular carcinoma‐associated antigen‐519/targeting protein for Xklp‐2 (HCA519/TPX2), for HCC that might be beneficial for T‐cell specific HCC immunotherapy.

Methods

HCC was studied for the expression for 15 tumor‐associated antigens considered useful for immunotherapy within three HCC cell lines (HepG2, Hep3B, and PLC/PRF/5), lymphocytes, non‐cancerous livers, and clinical HCC. The expression of tumor antigenic precursor proteins (TAPPs) messenger RNA was first screened by reverse transcriptase quantitative real‐time polymerase chain reaction.

Results

Four antigens (alpha fetoprotein, aspartyl/asparaginyl β­hydroxylase, glypican­3 and HCA519/TPX2) proved to be the best expressed TAPPs within the HCC specimens by molecular analyses. HCA519/TPX2 was detected by intracellular cell flow cytometry within HCC cell lines by using a specific antibody towards this TAPP. This antibody also detected the protein within primary HCCs. We synthesized two HCA519/TPX2 peptides (HCA519_464–472 and HCA519_351–359) which can bind to human leukocyte antigen (HLA)‐A*0201. Dendritic cells pulsed with these peptides stimulated cytolytic T lymphocytes (CTLs). These killer T‐cells lysed HLA‐A*0201+ T2 cells exogenously loaded with the correct specific peptide. The CTLs killed HepG2 (HLA‐A2+ and HCA519+), but not the Hep3B and PLC/PRF/5 cell lines, which are HCA519+ but HLA‐A2‐negative. In silico analysis reveals that HCA519/TPX2 has the inherent ability to bind to a very wide variety of HLA antigens.

Conclusion

HCA519/TPX2 is a viable immunotarget that should be further investigated within HCC patients.

Splicing regulator SLU7 is essential for maintaining liver homeostasis

A precise equilibrium between cellular differentiation and proliferation is fundamental for tissue homeostasis. Maintaining this balance is particularly important for the liver, a highly differentiated organ with systemic metabolic functions that is endowed with unparalleled regenerative potential. Carcinogenesis in the liver develops as the result of hepatocellular de-differentiation and uncontrolled proliferation. Here, we identified SLU7, which encodes a pre-mRNA splicing regulator that is inhibited in hepatocarcinoma, as a pivotal gene for hepatocellular homeostasis. SLU7 knockdown in human liver cells and mouse liver resulted in profound changes in pre-mRNA splicing and gene expression, leading to impaired glucose and lipid metabolism, refractoriness to key metabolic hormones, and reversion to a fetal-like gene expression pattern. Additionally, loss of SLU7 also increased hepatocellular proliferation and induced a switch to a tumor-like glycolytic phenotype. Slu7 governed the splicing and/or expression of multiple genes essential for hepatocellular differentiation, including serine/arginine-rich splicing factor 3 (Srsf3) and hepatocyte nuclear factor 4α (Hnf4α), and was critical for cAMP-regulated gene transcription. Together, out data indicate that SLU7 is central regulator of hepatocyte identity and quiescence.

The molecular basis for the pharmacokinetics and pharmacodynamics of curcumin and its metabolites in relation to cancer

This review addresses the oncopharmacological properties of curcumin at the molecular level. First, the interactions between curcumin and its molecular targets are addressed on the basis of curcumin's distinct chemical properties, which include H-bond donating and accepting capacity of the β-dicarbonyl moiety and the phenylic hydroxyl groups, H-bond accepting capacity of the methoxy ethers, multivalent metal and nonmetal cation binding properties, high partition coefficient, rotamerization around multiple C-C bonds, and the ability to act as a Michael acceptor. Next, the in vitro chemical stability of curcumin is elaborated in the context of its susceptibility to photochemical and chemical modification and degradation (e.g., alkaline hydrolysis). Specific modification and degradatory pathways are provided, which mainly entail radical-based intermediates, and the in vitro catabolites are identified. The implications of curcumin's (photo)chemical instability are addressed in light of pharmaceutical curcumin preparations, the use of curcumin analogues, and implementation of nanoparticulate drug delivery systems. Furthermore, the pharmacokinetics of curcumin and its most important degradation products are detailed in light of curcumin's poor bioavailability. Particular emphasis is placed on xenobiotic phase I and II metabolism as well as excretion of curcumin in the intestines (first pass), the liver (second pass), and other organs in addition to the pharmacokinetics of curcumin metabolites and their systemic clearance. Lastly, a summary is provided of the clinical pharmacodynamics of curcumin followed by a detailed account of curcumin's direct molecular targets, whereby the phenotypical/biological changes induced in cancer cells upon completion of the curcumin-triggered signaling cascade(s) are addressed in the framework of the hallmarks of cancer. The direct molecular targets include the ErbB family of receptors, protein kinase C, enzymes involved in prostaglandin synthesis, vitamin D receptor, and DNA.

Insulin-like growth factor I regulates the expression of isoforms of Wilms' tumor 1 gene in breast cancer

Aim and background

The Wilms' tumor 1 gene (WT1) is overexpressed in many cancers, including breast cancer, and its high expression is an adverse prognostic factor. However, the factors that regulate WT1 expression are poorly understood.

Methods and study design

Expression of genes at the RNA and protein level was detected by reverse transcriptase-polymerase chain reaction, western blotting, and reverse-phase protein array assays in breast cancer cell lines and tumor samples.

Results

In the study, we showed that the treatment of MCF-7 breast cancer cells with insulin-like growth factor I (IGF-I) increases WT1 protein expression by 77%. IGF-I uses Akt to up-regulate WT1 expression. Conversely, inhibition of IGF-I by IGF-binding protein 3 and of IGF-I receptor (IGF-IR) by anti-IGF-IR antibody (α-IR3) uses Akt to decrease WT1 protein levels in MCF-7 cells. We thus newly identified a mechanism by which IGF-I up-regulates WT1, especially the (+exon 5/-KTS) isoform, at the post-transcriptional level in MCF-7 cells and primary breast tumor samples.

Conclusions

The results indicate a novel posttranscriptional regulatory factor of WT1 in MCF-7 breast cancer cells.

Wilms' tumor 1 gene modulates Fas-related death signals and anti-apoptotic functions in hepatocellular carcinoma

BACKGROUND

The Wilms' tumor 1 (WT1) gene is known to be overexpressed in hepatocellular carcinoma (HCC) and to upregulate tumor growth and oncogenic potential, although the detailed mechanisms remain to be elucidated.

METHODS

We identified host genes involved in WT1 gene modulation of human liver cancer cell lines in vitro, and further characterized genes related to apoptosis. Moreover, we evaluated the alteration of genes by WT1 in 40 HCC and 58 non-HCC human liver samples collected at resection.

RESULTS

Analysis of the effect of small interfering RNAs-mediated knock-down of WT1 on apoptosis using an annexin V labeling assay, and on modulation of the activity of caspases-3, -8 and -9, indicated that WT1 has an anti-apoptotic role. We identified three apoptosis-related genes that were modulated by WT1; the cellular FLICE-inhibitory proteins (cFLIP) gene was upregulated, and Fas-associated death domain (FADD) and nuclear factor kappa B (NF-κB) were downregulated. Interestingly, knock-down of FADD or NF-κB resulted in the upregulation of WT1, and the expression of cFLIP changed in parallel with WT1 expression. We further evaluated WT1-mediated alteration of genes in HCC and non-HCC human liver samples. Both HCC and non-HCC tissues that expressed relatively high levels of WT1 showed cFLIP overexpression.

CONCLUSIONS

WT1 modulates cFLIP, FADD and NF-κB, and has an anti-apoptotic role in HCC. This mechanism of action of WT1 could be related to the tumor growth and oncogenic potential of HCC.

Control of epigenetic states by WT1 via regulation of de novo DNA methyltransferase 3A

Although tumour suppressor gene hypermethylation is a universal feature of cancer cells, little is known about the necessary molecular triggers. Here, we show that Wilms' tumour 1 (WT1), a developmental master regulator that can also act as a tumour suppressor or oncoprotein, transcriptionally regulates the de novo DNA methyltransferase 3A (DNMT3A) and that cellular WT1 levels can influence DNA methylation of gene promoters genome-wide. Specifically, we demonstrate that depletion of WT1 by short-interfering RNAs leads to reduced DNMT3A in Wilms' tumour cells and human embryonal kidney-derived cell lines. Chromatin immunoprecipitation assays demonstrate WT1 recruitment to the DNMT3A promoter region and reporter assays confirm that WT1 directly transactivates DNMT3A expression. Consistent with this regulatory role, immunohistochemical analysis shows co-expression of WT1 and DNMT3A proteins in nuclei of blastemal cells in human fetal kidney and Wilms' tumours. Using genome-wide promoter methylation arrays, we show that human embryonal kidney cells over-expressing WT1 acquire DNA methylation changes at specific gene promoters where DNMT3A recruitment is increased, with hypermethylation being associated with silencing of gene expression. Elevated DNMT3A is also demonstrated at hypermethylated genes in Wilms' tumour cells, including a region of long-range epigenetic silencing. Finally, we show that depletion of WT1 in Wilms' tumour cells can lead to reactivation of gene expression from methylated promoters, such as TGFB2, a key modulator of epithelial-mesenchymal transitions. Collectively, our work defines a new regulatory modality for WT1 involving elicitation of epigenetic alterations which is most likely crucial to its functions in development and disease.

Expression of Wilms' tumor 1 (WT1) in oral squamous cell carcinoma

BACKGROUND

The product of the Wilms' tumor gene, WT1 protein, is a tumor antigen for various kinds of cancer, and WT1 peptide-based cancer immunotherapy is widely anticipated as a new possibility for cancer treatment. The aim of this study was to investigate the expression of WT1 from quantitative and morphological perspectives in oral squamous cell carcinoma (OSCC), the most widespread malignant neoplasm of the oral cavity.

METHODS

Six OSCC cell lines and tissue sections from 29 OSCC patients were analyzed. To detect WT1 expression, reverse transcription-polymerase chain reaction analysis (RT-PCR), real-time PCR, Western blots, and immunofluorescence flow cytometry for WT1 were performed on the cell lines, and immunohistochemistry and fluorescence in situ hybridization (FISH) were performed on the tissue sections.

RESULTS

WT1 mRNA was found overexpressed in one of the six OSCC cell lines, with expression levels higher than that seen in human leukemia cell line (K562). Immunohistochemical analysis of tissue sections showed overexpression of WT1 protein in two patients, concentrated mainly in the cytoplasm of the outer one to three cell layers of the cancer nests. This was consistent with the expression of WT1 mRNA observed by FISH. Meanwhile, WT1 was not detected on normal oral epithelium. WT1 protein was detected on actively proliferating cancer nests and even on elongated epithelial ridge where new droplet-cancer-nests were being formed and starting infiltration toward subepithelial layer.

CONCLUSIONS

The results suggest that WT1 plays an important role in the pathogenesis of some types of OSCC, particularly in proliferation of the cancer cells.

Novel report of expression and function of CD97 in malignant gliomas: correlation with Wilms tumor 1 expression and glioma cell invasiveness

OBJECT

The Wilms tumor 1 (WT1) protein-a developmentally regulated transcription factor-is aberrantly expressed in gliomas and promotes their malignant phenotype. However, little is known about the molecular allies that help it mediate its oncogenic functions in glioma cells.

METHODS

The authors used short interfering RNA (siRNA) to suppress WT1 expression in glioblastoma (GBM) cells and evaluated the effect of this on GBM cell invasiveness. Gene expression analysis was then used to identify the candidate genes that were altered as a result of WT1 silencing. One candidate target, CD97, was then selected for further investigation into its role by suppressing its expression using siRNA silencing, followed by proliferation and invasion assays.

RESULTS

WT1 levels were reliably and reproducibly suppressed by siRNA application. This resulted in a significant decrease in cellular invasiveness. Microarray analyses identified the gene products that were consistently downregulated (27) and upregulated (11) with WT1 silencing. Of these, CD97 expression was consistently suppressed across the 3 different GBM cell lines studied and was found on further investigation to significantly impact GBM cell invasiveness.

CONCLUSIONS

Although CD97 expression in gliomas has not been described previously, we conclude that the possible upregulation of CD97 mediated by WT1 promotes cellular invasiveness-one of the most characteristic and challenging aspects of glial tumor cells. Further studies are needed to clarify the nature of this regulation and its impact, as CD97 could represent a novel target for antiglioma therapies.

RNAa-mediated overexpression of WT1 induces apoptosis in HepG2 cells

Aim

Recent studies have reported that double-stranded RNA (dsRNA) can activate gene expression by targeting promoter sequence in a process termed RNA activation. The present study was conducted to evaluate the potential of WT1 induction by small activating RNA targeting the WT1 promoter (dsWT1) in the treatment of hepatocellular carcinoma.

Methods

The human hepatocellular carcinoma cell line HepG2 was transfected with dsRNA by liposomes. The expression of mRNA and protein in cells were investigated using real-time reverse real-time quantitative PCR and Western blot, respectively. Cell viability and clonogenicity were determined by MTT assay and clonogenicity assay, respectively. Cell apoptosis was evaluated by flow-cytometric analysis.

Results

Expressions of WT1 mRNA and protein in dsWT1 treated HepG2 cells were significantly elevated. Inhibition of cell viability by dsWT1 was dose-dependent and time-dependent. Reduction of the number and size of colonies formed were found in dsWT1 treated cells. dsWT1 induced significant apoptosis in HepG2 cells. The decreased anti-apoptotic protein Bcl-2 and elevated pro-apoptotic protein Bak expression were detected in dsWT1 treated cells. The level of pro-caspase-3 remarkably decreased and cleaved caspase-3 and PARP fragment were also detected in dsWT1 treated cells.

Conclusion

These data show that RNAa-mediated overexpression of WT1 may have therapeutic potential in the treatment of hepatocellular carcinoma.

Expression of Wilms tumor 1 gene in a variety of pediatric tumors

BACKGROUND/PURPOSE

Wilms tumor 1 (WT1) gene is overexpressed in many types of neoplasms, thus suggesting that WT1 has oncogenic properties. Therefore, WT1 is a molecular target for cancer therapy. The objectives of this study were to evaluate the WT1 gene expression in various pediatric tumors and to elucidate that WT1 can be a target of cancer therapy in pediatric malignancies.

PATIENTS AND METHODS

The expression of WT1 protein was examined in 60 cases of primary pediatric tumors. The levels of WT1 messenger RNA (mRNA) expression were examined by a quantitative real-time reverse transcriptase polymerase chain reaction analysis in frozen tissue samples from 56 cases with pediatric tumors.

RESULTS

Immunohistochemical staining revealed that WT1 protein was widely detected in pediatric malignancies. The alveolar subtype of rhabdomyosarcoma showed more intensive staining than the embryonal subtype. The positive rate of the alveolar type was significantly higher than that of the embryonal type. The expression of WT1 mRNA in the tumor samples varied widely. However, no significant correlation was observed between WT1 mRNA expression and clinical factors.

CONCLUSION

The WT1 expression was broadly detected in various pediatric neoplasms. These results indicate that WT1 may therefore be a potentially useful therapeutic target in most of pediatric malignancies.

Transcriptional analysis of doxorubicin-induced cytotoxicity and resistance in human hepatocellular carcinoma cell lines

BACKGROUND/AIMS

Hepatoma is either intrinsically resistant to chemotherapy or response to it but later develop resistance. The aim of this study was to clarify the relationship of treatment with doxorubicin (Dox) in hepatoma HepG2 cells and drug resistance developed by Dox.

METHODS

We have analysed the bioactivities and gene expression profiles of multidrug resistant (MDR) HepG2/DR cell line and its parental HepG2 cell, which were exposure to Dox.

RESULTS

We confirmed that Dox-induced apoptosis of HepG2 cells in a time-dependent manner; cDNA microarray and hierarchical cluster analysis demonstrate that the features of the transcriptional programme of the later response to Dox in HepG2 cells and MDR HepG2/DR cells have a common character, which is upregulation of stress response, cytoskeleton, ubiquitin-proteasome pathway and repressed G-protein signal transduction system; differentially expressed genes in MDR HepG2/DR such as drug transporters and tumour-associated antigens were verified at the levels of mRNA by semiquantitative reverse transcriptase-polymerase chain reaction.

CONCLUSIONS

These results reveal novel co-ordinated changes that occurred in resistant HepG2 cells to survive from cell apoptosis elicited by Dox treatment.