Oncogenic Role of ADAM32 in Hepatoblastoma: A Potential Molecular Target for Therapy.

Outcomes of pediatric hepatoblastoma (HBL) have improved, but refractory cases still occur. More effective and safer drugs are needed that are based on molecular mechanisms. A disintegrin and metalloproteases (ADAMs) are expressed with high frequency in various human carcinomas and play an important role in cancer progression. In this study, we analyzed expression of ADAMs in HBL with a cDNA microarray dataset and found that the expression level of ADAM32 is particularly high. To investigate the role of ADAM32 in cancer, forced expression or knockdown experiments were conducted with HepG2 and HBL primary cells. Colony formation, cell migration and invasion, and cell viability were increased in HepG2 expressing ADAM32, whereas knockdown of ADAM32 induced a decrease in these cellular functions. Quantitative RT-PCR demonstrated an association between ADAM32 expression and the expression of genes related to cancer stem cells and epithelial-mesenchymal transition (EMT), suggesting a role of ADAM32 in cancer stemness and EMT. Furthermore, knockdown of ADAM32 increased cisplatin-induced apoptosis, and this effect was attenuated by a caspase-8 inhibitor, suggesting that ADAM32 plays a role in extrinsic apoptosis signaling. We conclude that ADAM32 plays a crucial role in progression of HBL, so it might be a promising molecular target in anticancer therapy.

In Vitro Transfection of Up-Regulated Genes Identified in Favorable-Outcome Neuroblastoma into Cell Lines.

We previously used microarrays to show that high expression of DHRS3, NROB1, and CYP26A1 predicts favorable NB outcomes. Here, we investigated whether expression of these genes was associated with suppression of NB cell (SK-N-SH, NB12, and TGW) growth. We assessed morphology and performed growth, colony-formation, and migration assays, as well as RNA sequencing. The effects of the transient expression of these genes were also assessed with a tetracycline-controlled expression (Tet-On) system. Gene overexpression reduced cell growth and induced morphological senescence. Gene-expression analysis identified pathways involving cellular senescence and cell adhesion. In these cells, transduced gene dropout occurred during passage, making long-term stable gene transfer difficult. Tet-On-induced gene expression caused more pronounced cell-morphology changes. Specifically, DHRS3 and NROB1 led to rapid inhibition and arrest of cell growth, though CYP26A1 did not affect cell-growth rate or cell cycle. DHRS3 arrested the cell cycle by interacting with the all-trans-retinol pathway and drove differentiation and senescence in tumors. Overexpression of these genes reduced the malignant grade of these cells. A new therapeutic strategy might be the induction of these genes, as they suppress the growth of high-risk neuroblastoma and lead to differentiation and senescence.

Clinical features of ATRX or DAXX mutated neuroblastoma.

PURPOSE: Previously, we reported that alternative lengthening of telomere (ALT) may be a biomarker for chemo-sensitivity and late recurrence in neuroblastoma (NBL). In this study, alterations of ATRX or DAXX, which both encode chromatin remodeling proteins in telomeric region, and their relationship to ALT were examined in NBLs. METHODS: Our previous report on 121 NBLs revealed 11 NBLs with elongated telomeres by ALT. In these NBLs, ATRX or DAXX gene alterations were identified using next-generation sequencing and compared to clinical and other biological factors. RESULTS: In 11 ALT cases, DAXX mutations were detected in one case, and ATRX alterations were detected in 10 cases. Except for one case, no DAXX or ATRX alterations were detected in 110 tumors with normal or shortened telomeres. MYCN amplification was not detected in ATRX altered tumors. In ALT cases, three infants showed ATRX deletions, and all seven cases detected after 18months of age showed poor prognosis. CONCLUSIONS: In NBLs, ALT was caused by ATRX or DAXX alterations. ATRX altered cases without MYCN amplification detected at greater than 18months showed poor prognosis, suggesting that ATRX or DAXX alterations are a particular NBL subtype. Since these tumors showed chemo-resistance and late recurrence, complete resection in a surgical approach should be performed to improve patient prognosis.

Detection of MYCN amplification using blood plasma: noninvasive therapy evaluation and prediction of prognosis in neuroblastoma.

PURPOSE: Amplification of neuroblastoma derived (avian)v-myc myelocytomatosis viral related oncogene (MYCN) is an important risk-stratified indicator in neuroblastoma. To evaluate the feasibility of noninvasive measurement of MYCN amplification, we analyzed MYCN amplification in stored blood plasma samples. METHODS: We used quantitative real-time PCR to determine MYCN copy numbers in plasma-derived DNA of 10 healthy volunteers and 50 neuroblastoma cases. The copy number was calculated as the ratio of copies of MYCN to those of a reference gene. Plasma samples obtained after surgery or neoadjuvant therapy were also analyzed in five cases and four cases, respectively. RESULTS: In 34 neuroblastoma cases, MYCN was nonamplified in both tumor tissue and blood plasma. In 16 neuroblastoma cases, MYCN was amplified in both tumor tissue and blood plasma; 13 of the 16 cases showed poor outcomes. MYCN amplification was undetectable in blood plasma shortly after surgery or neoadjuvant therapy. The correlation coefficient between MYCN copy numbers in tumor tissue and in blood plasma was approximately 0.9. CONCLUSION: We can detect MYCN amplification of tumor tissue noninvasively and quantitatively by measuring the MYCN copy number in blood plasma. Determination of MYCN copy number in plasma may be useful when evaluating surgery and neoadjuvant chemotherapy.

Characterization of common marmoset (Callithrix jacchus) bone marrow-derived mesenchymal stem cells.

Mesenchymal stem cells (MSCs) could be useful for regenerative medicine because they can beharvested easily from the bone marrow of living donors and the cells can be differentiated into adipogenic, osteogenic, and chondrogenic lineages in vitro. To apply MSCs for the medical treatment of human diseases as regenerative medicine, detailed experimental characterization of the cells is required. Recently, a New World primate, the common marmoset (Callithrix jacchus), has been widely used as a new human disease model because of its ease of handling and breeding. Although common marmoset MSCs have been established and will be used in preclinical studies of regenerative medicine, the characteristics of these cells remain unclear. Aiming to characterize common marmoset MSCs further, we harvested common marmoset bone marrow-derived cells (cmBMDCs) from the femurs of newborn males. We revealed that the morphology of the cells was similar to common marmoset fibroblasts, and extracellular matrix components, such as gelatin and fibronectin, were effective for their proliferation and formation of colony-forming unit fibroblasts. Furthermore, we were able to differentiate cmBMDCs into adipocytes, osteocytes, and chondrocytes in vitro, and they expressed the MSCmarkers CD44, CD73, CD90, and CD105, but their expression decreased with increasing passage number. The data demonstrate that cmBMDCs exhibit characteristics of MSCs and thus it would be beneficial to use these cells in preclinical studies.

Elevation of urine trypsinogen 2 is an independent risk factor for pancreatic fistula after pancreaticoduodenectomy.

OBJECTIVES: Previous reports suggested that the urine trypsinogen 2 (U-TRP2) test might be a valuable method for the diagnosis of postoperative pancreatitis after pancreatic surgery. We hypothesize that the elevation of U-TRP2 level after pancreaticoduodenectomy (PD) could be associated with the occurrence of postoperative pancreatic fistula (POPF). METHODS: A total of 130 consecutive patients undergoing PD with duct-to-mucosa pancreaticogastrostomy were included. Urine samples for evaluation of U-TRP2 levels were collected prospectively. Risk factors for POPF were evaluated using univariate and multivariate analyses. RESULTS: Of 130 patients, 19 developed POPF; grade A in 14 (11%), grade B in 3 (2%), and grade C in 1 (1%). Univariate analysis demonstrated that a nonobstructed main pancreatic duct, a pancreatic duct less than 3 mm, soft texture of the pancreatic gland, a PD with antrectomy, PD with hepatic resection, hyperamylasemia, and elevation of U-TRP2 levels (>50 µg/L) were significantly associated with POPF (P < 0.05). By multivariate analysis, elevation of U-TRP2 levels (odds ratio = 4.544, P = 0.029) was the only independent risk factor that correlated with POPF. CONCLUSIONS: Elevation of U-TRP2 level is an independent risk factor for POPF after PD. Elevated U-TRP2 level might be the consequence of the postoperative pancreatitis, and postoperative pancreatitis may play an important role in the pathogenic mechanism of POPF after PD.

Neoplastic transformation by TERT in FGF-2-expanded human mesenchymal stem cells.

The low percentage of human mesenchymal stem cells (hMSCs) in bone marrow necessitates their in vitro expansion prior to clinical use in regenerative medicine. We evaluated the effect of long-term culture of hMSCs on telomere length and transformation capacity by TERT transfection. hMSCs were isolated from the bone marrow aspirates of 24 donors and cultured with fibroblast growth factor-2 (FGF-2). Six cell lines with >500 population doubling levels were considered immortalized. TERT was transfected into two of the six lines for a comparison of telomere length, telomerase activity, differential capacity, colony formation capacity in soft agar and tumorigenicity in immunodeficient (NOD-SCID) mice. hMSC lines exhibited elongated telomeres without the activation of telomerase and retained multi-lineage differentiation potential upon chondrogenic or adipogenic differentiation, while non-immortalized hMSCs showed a marked reduction in telomere length in the differentiation process. Immortalized hMSCs showed anchorage-independence and formed tumors in NOD-SCID mice. Histologically, these tumors consisted of differentiated cells such as fat tissue and cartilage. Two TERT-transfected hMSC lines showed high rates of tumor formation in NOD-SCID mice. These tumors were histologically similar to teratocarcinoma without differentiated cells. These cells may provide a model for the origin of cancer stem cells from adult stem cells, and indicate the possibility that telomerase activation has a major role in the malignant transformation of human stem cells. These data suggest that adult hMSCs have a potential for neoplastic transformation and have implications for the use of hMSCs in tissue engineering and regenerative medicine.

Regulation of chromatin and chromosome morphology by histone H3 modifications in pig oocytes.

Oocyte growth, maturation, and activation are complex processes that include transcription, heterochromatin formation, chromosome condensation and decondensation, two consecutive chromosome separations, and genomic imprinting. The objective of this study was to investigate changes in histone H3 modifications in relation to chromatin/chromosome morphology in pig oocytes during their growth, maturation, and activation. During the growth phase, histone H3 was acetylated at lysines 9, 14, and 18 (K9, K14, and K18), and became methylated at K9 when the follicles developed to the antral stage (oocyte diameter, 90 mum). When the fully grown oocytes (diameter, 120 mum) started their maturation, histone H3 became phosphorylated at serine 28 (S28) and then at S10, and deacetylated at K9, K14, and K18 as the chromosomes condensed. After the electroactivation of mature oocytes, histone H3 was reacetylated and dephosphorylated concomitant with the decondensation of the chromosomes. Histone H3 kinase activity increased over a similar time course to that of the phosphorylation of histone H3-S28 during oocyte maturation, and this activity decreased as histone H3-S10 and H3-S28 began to be dephosphorylated after the activation of the mature oocytes. These results suggest that the chromatin morphology of pig oocytes is regulated by the acetylation/deacetylation and the phosphorylation/dephosphorylation of histone H3, and the phosphorylation of histone H3 is the key event in meiotic chromosome condensation in oocytes. The inhibition of histone deacetylase with trichostatin A (TSA) inhibited the deacetylation and phosphorylation of histone H3, and chromosome condensation. Therefore, the deacetylation of histone H3 is thought to be required for its phosphorylation in meiosis. Although histone H3 acetylation and phosphorylation were reversible, the histone methylation that was established during the oocyte growth phase was stable throughout the course of oocyte maturation and activation.

Involvement of histone H3 (Ser10) phosphorylation in chromosome condensation without Cdc2 kinase and mitogen-activated protein kinase activation in pig oocytes.

When oocytes resume meiosis, chromosomes start to condense and Cdc2 kinase becomes activated. However, recent findings show that the chromosome condensation does not always correlate with the Cdc2 kinase activity in pig oocytes. The objectives of this study were to examine 1) the correlation between chromosome condensation and histone H3 phosphorylation at serine 10 (Ser10) during the meiotic maturation of pig oocytes and 2) the effects of protein phosphatase 1/2A (PP1/ PP2A) inhibitors on the chromosome condensation and the involvement of Cdc2 kinase, MAP kinase, and histone H3 kinase in this process. The phosphorylation of histone H3 (Ser10) was first detected in the clump of condensed chromosomes at the diakinesis stage and was maintained until metaphase II. The kinase assay showed that histone H3 kinase activity was low in oocytes at the germinal vesicle stage (GV) and increased at the diakinesis stage and that high activity was maintained until metaphase II. Treatment of GV-oocytes with okadaic acid (OA) or calyculin-A (CL-A), the PP1/PP2A inhibitors, induced rapid chromosome condensation with histone H3 (Ser10) phosphorylation after 2 h. Both histone H3 kinase and MAP kinase were activated in the treated oocytes, although Cdc2 kinase was not activated. In the oocytes treated with CL-A and the MEK inhibitor U0126, neither Cdc2 kinase nor MAP kinase were activated and no oocytes underwent germinal vesicle breakdown (GVBD), although histone H3 kinase was still activated and the chromosomes condensed with histone H3 (Ser10) phosphorylation. These results suggest that the phosphorylation of histone H3 (Ser10) occurs in condensed chromosomes during maturation in pig oocytes. Furthermore, the chromosome condensation is correlated with histone H3 kinase activity but not with Cdc2 kinase and MAP kinase activities.