Shota Uekusa

The clinical course in pediatric solid tumor patients with focal nodular hyperplasia of the liver

BackgroundFocal nodular hyperplasia (FNH) of the liver is a rare benign lesion that may be related to the vascular and hepatic damage induced by completion of tumor therapy and a reaction to localized vascular abnormality. The aim of this study was to analyze the clinical course in pediatric solid tumor patients with FNH.MethodsWe analyzed thirty-two patients with pediatric solid tumors who received multiagent chemotherapy (15 advanced neuroblastomas, 7 hepatoblastomas, 5 rhabdomyosarcomas, 2 nephroblastomas, 1 rhabdoid tumor of the kidney, 1 clear cell sarcoma of the kidney and 1 pancreatoblastoma). All of them had been previously treated at our hospital, and have been alive for over 3 years without recurrence.ResultsFNH lesions were discovered in three (9.4%) of 32 patients, and were neuroblastoma (NB) stage 4. All 3 patients received induction chemotherapy and high-dose alkylating agents, and developed grade 3 (National Cancer Institute Common Toxicity Criteria; NCI-CTC) liver dysfunction during completion of tumor therapy without veno-occlusive disease. Two of the 3 patients received the same induction chemotherapy and high doses of alkylating agents with total body irradiation for cytoreductive agents prior to peripheral blood cell transplantation. FNH lesions in both female patients who received estrogen replacement therapy after completion of tumor therapy have expanded and are increasing.ConclusionFNH appears to be a late complication of iatrogenic disease in NB stage 4 patients. The therapeutic agents for NB stage 4 and estrogen replacement therapy should be considered as risk factors for the development of FNH.

Successful treatment for hepatoblastoma in a 1‐year‐old boy with trisomy 18

type GCT, relapses may occur even decades after diagnosis, although the survival rate is 95% if diagnosed in the early stages. The presented case indicates the need to emphasize the possibility of occurrence of endocrinological disorders as a symptom of hormone-secreting tumors in children. GnRh-independent precocious puberty may be the first symptom of hormone-secreting ovarian tumors in children, even if tumors are not detectable in preliminary radiologic examinations. In such cases, profound diagnostics with systematic ultrasound examination are essential.

Mesenchymal hamartoma of the liver originating in the caudate lobe with t(11;19)(q13;q13.4): Report of a case

We herein report the case of a 35-month-old female child presenting with mesenchymal hamartoma of the liver (MHL), with t(11;19)(q13;q13.4) originating in the caudate lobe. This case is the eighth known description of a cytogenetic abnormality in mesenchymal hamartoma of the liver. It is similar to the seven cases previously reported, in that one of the breakpoints involves the chromosome band 19q13.3 or 19q13.4, but it is the first report of an abnormality originating in the caudate lobe.

Nr4a3, a possibile oncogenic factor for neuroblastoma associated with CpGi methylation within the third exon

Aberrant methylation of Nr4a3 exon 3 CpG island (CpGi) was initially identified during multistep mouse skin carcinogenesis. Nr4a3 is also known as a critical gene for neuronal development. Thus, we examined the Nr4a3 exon 3 CpGi methylation in mouse brain tissues from 15-day embryos, newborns and 12-week-old adults and found significant increase of its methylation and Nr4a3 expression during mouse brain development after birth. In addition, homologous region in human genome was frequently and aberrantly methylated in neuroblastoma specimens. A quantitative analysis of DNA methylation revealed that hypomethylation of CpG islands on NR4A3 exon 3, but not on exon 1 was identified in three neuroblastomas compared with matched adrenal glands. Additional analysis for 20 neuroblastoma patients was performed and 8 of 20 showed hypomethylation of the CpGi on NR4A3 exon 3. The survival rate of those 8 patients was significantly lower compared with those in patients with hypermethylation. Immunohistochemical NR4A3 expression was generally faint in neuroblastoma tissues compared with normal tissues. Moreover, the MYCN amplified NB9 cell line showed hypomethylation and low expression of NR4A3, while the non-MYCN amplified NB69 cell line showed hypermethylation and high expression. These results indicate that DNA hypomethylation of the CpGi at NR4A3 exon 3 is associated with low NR4A3 expression, and correlates with poor prognosis of neuroblastoma. Since NR4A3 upregulation associated with the hypermethylation and neuronal differentiation in mice, poor prognosis of neuroblastoma associated with NR4A3 low expression may be partly explained by dysregulation of its differentiation.

Identification of a novel E-box binding pyrrole-imidazole polyamide inhibiting MYC-driven cell proliferation

The MYC transcription factor plays a crucial role in the regulation of cell cycle progression, apoptosis, angiogenesis, and cellular transformation. Due to its oncogenic activities and overexpression in a majority of human cancers, it is an interesting target for novel drug therapies. MYC binding to the E‐box (5′‐CACGTGT‐3′) sequence at gene promoters contributes to more than 4000 MYC‐dependent transcripts. Owing to its importance in MYC regulation, we designed a novel sequence‐specific DNA‐binding pyrrole–imidazole (PI) polyamide, Myc‐5, that recognizes the E‐box consensus sequence. Bioinformatics analysis revealed that the Myc‐5 binding sequence appeared in 5′‐ MYC binding E‐box sequences at the eIF4G1, CCND1, and CDK4 gene promoters. Furthermore, ChIP coupled with detection by quantitative PCR indicated that Myc‐5 has the ability to inhibit MYC binding at the target gene promoters and thus cause downregulation at the mRNA level and protein expression of its target genes in human Burkitts lymphoma model cell line, P493.6, carrying an inducible MYC repression system and the K562 (human chronic myelogenous leukemia) cell line. Single i.v. injection of Myc‐5 at 7.5 mg/kg dose caused significant tumor growth inhibition in a MYC‐dependent tumor xenograft model without evidence of toxicity. We report here a compelling rationale for the identification of a PI polyamide that inhibits a part of E‐box‐mediated MYC downstream gene expression and is a model for showing that phenotype‐associated MYC downstream gene targets consequently inhibit MYC‐dependent tumor growth.

Non-promoter DNA hypermethylation of Zygote Arrest 1 (ZAR1) in neuroblastomas

BACKGROUND The comprehensive methylation analysis of tumor-specific differently methylated regions in malignant melanomas and brain tumors has led to the identification of non-promoter hypermethylation of zygote arrest 1 (ZAR1). To search the non-promoter ZAR1 hypermethylation in neuroblastomas, we analyzed the levels of the methylation and transcript expression of ZAR1. METHODS The MassARRAY® EpiTYPER (Sequenom Inc., San Diego, CA, USA) system was optimized to determine the quantitative methylation levels of ZAR1 for 12 neuroblastoma cell lines, 23 neuroblastoma samples and four adrenal samples. ZAR1 expression levels were evaluated through a quantitative, real-time reverse transcription-polymerase chain reaction. The quantitative methylation levels of ZAR1 were subjected to correlation studies with the established markers of progressive disease and outcome. RESULTS Strikingly, the hypermethylation of ZAR1 regions and ZAR1 expression levels was observed in the neuroblastoma cell lines and neuroblastoma samples, compared to the adrenal samples. Somatic changes in ZAR1 methylation and ZAR1 expression were found in all three neuroblastoma patients. In the ZAR1 regions, poor-outcome tumors that were MYCN-amplified and/or Stage 3 or 4 and/or the age at diagnosis was≥18months, and/or showed an unfavorable histology were frequently hypermethylated. CONCLUSION Our results indicate that the hypermethylation of ZAR1 regions is extremely frequent in neuroblastomas and correlates with established markers of progressive disease and outcome.

Identification of aberrant methylation regions in neuroblastoma by screening of tissue-specific differentially methylated regions†‡§

The identification of tissue‐specific differentially methylated regions (tDMRs) is key to our understanding of mammalian development. Research has indicated that tDMRs are aberrantly methylated in cancer and may affect the oncogenic process.

Usefulness of power Doppler ultrasonography and superparamagnetic iron oxide enhanced magnetic resonance imaging for diagnosis of focal nodular hyperplasia of the liver after treatment of neuroblastoma.

Focal nodular hyperplasia (FNH) of the liver is rare in children, and it is usually diagnosed through a biopsy of the liver or hepatectomy. The authors report a case of a 10-year-old girl with multiple focal nodular hyperplasia lesions of the liver after the completion of tumor therapy for advanced neuroblastoma, and review the usefulness of the combination of power Doppler ultrasonography (US) and superparamagnetic iron oxide (SPIO) enhanced magnetic resonance imaging (MRI) for the diagnosis of FNH without a biopsy of the liver or hepatectomy.

Depletion of TFAP2E attenuates adriamycin-mediated apoptosis in human neuroblastoma cells

Neuroblastoma is a childhood malignancy originating from the sympathetic nervous system and accounts for approximately 15% of all pediatric cancer-related deaths. To newly identify gene(s) implicated in the progression of neuroblastoma, we investigated aberrantly methylated genomic regions in mouse skin tumors. Previously, we reported that TFAP2E, a member of activator protein-2 transcription factor family, is highly methylated within its intron and its expression is strongly suppressed in mouse skin tumors compared with the normal skin. In the present study, we analyzed public data of neuroblastoma patients and found that lower expression levels of TFAP2E are significantly associated with a shorter survival. The data indicate that TFAP2E acts as a tumor suppressor of neuroblastoma. Consistent with this notion, TFAP2E-depleted neuroblastoma NB1 and NB9 cells displayed a substantial resistance to DNA damage arising from adriamycin (ADR), cisplatin (CDDP) and ionizing radiation (IR). Silencing of TFAP2E caused a reduced ADR-induced proteolytic cleavage of caspase-3 and PARP. Of note, compared with the untransfected control cells, ADR-mediated stimulation of CDK inhibitor p21WAF1 was markedly upregulated in TFAP2E‑knocked down cells. Therefore, our present findings strongly suggest that TFAP2E has a pivotal role in the regulation of DNA damage response in NB cells through the induction of p21WAF1.

ZAR1 knockdown promotes the differentiation of human neuroblastoma cells by suppression of MYCN expression

Although DNA hypermethylation at non-promoter region of the Zygote arrest 1 (ZAR1) gene has been observed in many types of tumor, including neuroblastoma (NB), the role of this gene in tumor development and/or progression is unclear. One reason is that knowledge about the function of ZAR1 protein is limited. Although it has been reported that ZAR1 plays a crucial role in early embryogenesis and may act as a transcriptional repressor for some transcripts, the detailed mechanism is still elusive. In the present study, we analyzed public data of NB patients and found that higher expression levels of ZAR1 were significantly associated with a shorter survival period. Consistent with this result, ZAR1-depleted NB cells showed well-differentiated phenotypes with elongated neurites and upregulated expression of TRKA and RET, which are markers for differentiated NB. Moreover, the expression level of MYCN protein was markedly suppressed in ZAR1-depleted NB cells. MYCN-depleted cells showed similar phenotypes to ZAR1-depleted cells. The present findings indicate that ZAR1 has oncogenic effects in NB by suppressing cell differentiation via regulation of MYCN expression.