UBE2C expression is elevated in hepatoblastoma and correlates with inferior patient survival.

Hepatoblastoma (HB) is the most common malignant liver tumor among children. To gain insight into the pathobiology of HB, we performed RNA sequence analysis on 5 patient-derived xenograft lines (HB-243, HB-279, HB-282, HB-284, HB-295) and 1 immortalized cell line (HUH6). Using cultured hepatocytes as a control, we found 2,868 genes that were differentially expressed in all of the HB lines on mRNA level. The most upregulated genes were ODAM, TRIM71, and IGDCC3, and the most downregulated were SAA1, SAA2, and NNMT. Protein-protein interaction analysis identified ubiquitination as a key pathway dysregulated in HB. UBE2C, encoding an E2 ubiquitin ligase often overexpressed in cancer cells, was markedly upregulated in 5 of the 6 HB cell lines. Validation studies confirmed UBE2C immunostaining in 20 of 25 HB tumor specimens versus 1 of 6 normal liver samples. The silencing of UBE2C in two HB cell models resulted in decreased cell viability. RNA sequencing analysis showed alterations in cell cycle regulation after UBE2C knockdown. UBE2C expression in HB correlated with inferior patient survival. We conclude that UBE2C may hold prognostic utility in HB and that the ubiquitin pathway is a potential therapeutic target in this tumor.

Bacterial translocation markers and toll-like receptors in biliary atresia following successful portoenterostomy.

AIM: The gut-liver axis may contribute to pathophysiology of cholestatic liver disorders like biliary atresia (BA) by bacterial translocation (BT). Toll-like receptors (TLR) are pattern recognition receptors known to activate innate immunity and secretion of inflammatory cytokines. Herein, we examined BT-associated biomarkers and TLRs in relation to liver injury after successful portoenterostomy (SPE) in BA. METHODS: Serum levels of lipopolysaccharide-binding protein (LBP), CD14, LAL, TNF-α, IL-6 and FABP2 along with liver expression of TLRs (TLR1, TLR4, TLR7 and TLR9), LBP and CD14 were measured during median 4.9 (1.7-10.6) years follow-up after SPE in 45 BA patients. RESULTS: Serum LBP, CD14, TNF-α and IL-6 all increased after SPE whereas LAL and FABP-2 remained unchanged. Serum LBP correlated positively with CD14 and markers of hepatocyte injury and cholestasis, but not with Metavir fibrosis stage, transcriptional markers for fibrosis (ACTA2) or ductular reaction. Serum CD14 concentration was significantly higher in patients with portal hypertension than without. While liver expression of TLR4 and LBP remained low, TLR7 and TLR1 showed marked BA-specific increases, and TLR7 correlated with Metavir fibrosis stage and ACTA2. CONCLUSION: BT does not seem to play a significant role in liver injury after SPE in our series of BA patients.

SLC-0111, an inhibitor of carbonic anhydrase IX, attenuates hepatoblastoma cell viability and migration.

Background: In response to hypoxia, tumor cells undergo transcriptional reprogramming including upregulation of carbonic anhydrase (CA) IX, a metalloenzyme that maintains acid-base balance. CAIX overexpression has been shown to correlate with poor prognosis in various cancers, but the role of this CA isoform in hepatoblastoma (HB) has not been examined. Methods: We surveyed the expression of CAIX in HB specimens and assessed the impact of SLC-0111, a CAIX inhibitor, on cultured HB cells in normoxic and hypoxic conditions. Results: CAIX immunoreactivity was detected in 15 out of 21 archival pathology HB specimens. The CAIX-positive cells clustered in the middle of viable tumor tissue or next to necrotic areas. Tissue expression of CAIX mRNA was associated with metastasis and poor clinical outcome of HB. Hypoxia induced a striking upregulation of CAIX mRNA and protein in three HB cell models: the immortalized human HB cell line HUH6 and patient xenograft-derived lines HB-295 and HB-303. Administration of SLC-0111 abrogated the hypoxia-induced upregulation of CAIX and decreased HB cell viability, both in monolayer and spheroid cultures. In addition, SLC-0111 reduced HB cell motility in a wound healing assay. Transcriptomic changes triggered by SLC-0111 administration differed under normoxic vs. hypoxic conditions, although SLC-0111 elicited upregulation of several tumor suppressor genes under both conditions. Conclusion: Hypoxia induces CAIX expression in HB cells, and the CAIX inhibitor SLC-0111 has in vitro activity against these malignant cells.

Analysis of Non-Relapsed and Relapsed Adult Type Granulosa Cell Tumors Suggests Stable Transcriptomes during Tumor Progression.

Adult-type granulosa cell tumor (AGCT) is a rare ovarian malignancy characterized by slow growth and hormonal activity. The prognosis of AGCT is generally favorable, but one-third of patients with low-stage disease experience a late relapse, and over half of them die of AGCT. To identify markers that would distinguish patients at risk for relapse, we performed Lexogen QuantSeq 3' mRNA sequencing on formalin-fixed paraffin-embedded, archival AGCT tissue samples tested positive for the pathognomonic Forkhead Box L2 (FOXL2) mutation. We compared the transcriptomic profiles of 14 non-relapsed archival primary AGCTs (follow-up time 17-26 years after diagnosis) with 13 relapsed primary AGCTs (follow-up time 1.7-18 years) and eight relapsed tumors (follow-up time 2.8-18.9 years). Non-relapsed and relapsed primary AGCTs had similar transcriptomic profiles. In relapsed tumors three genes were differentially expressed: plasmalemma vesicle associated protein (PLVAP) was upregulated (p = 0.01), whereas argininosuccinate synthase 1 (ASS1) (p = 0.01) and perilipin 4 (PLIN4) (p = 0.02) were downregulated. PLVAP upregulation was validated using tissue microarray RNA in situ hybridization. In our patient cohort with extremely long follow-up, we observed similar gene expression patterns in both primary AGCT groups, suggesting that relapse is not driven by transcriptomic changes. These results reinforce earlier findings that molecular markers do not predict AGCT behavior or risk of relapse.

Liver secretin receptor predicts portoenterostomy outcomes and liver injury in biliary atresia.

Biliary atresia (BA) is a chronic neonatal cholangiopathy characterized by fibroinflammatory bile duct damage. Reliable biomarkers for predicting native liver survival (NLS) following portoenterostomy (PE) surgery are lacking. Herein we explore the utility of 22 preidentified profibrotic molecules closely connected to ductular reaction (DR) and prevailing after successful PE (SPE), in predicting PE outcomes and liver injury. We used qPCR and immunohistochemistry in a BA cohort including liver samples obtained at PE (n = 53) and during postoperative follow-up after SPE (n = 25). Of the 13 genes over-expressed in relation to cholestatic age-matched controls at PE, only secretin receptor (SCTR) expression predicted cumulative 5-year NLS and clearance of jaundice. Patients in the highest SCTR expression tertile showed 34-55% lower NLS than other groups at 1-5 years after PE (P = 0.006-0.04 for each year). SCTR expression was also significantly lower [42 (24-63) vs 75 (39-107) fold, P = 0.015] among those who normalized their serum bilirubin after PE. Liver SCTR expression localized in cholangiocytes and correlated positively with liver fibrosis, DR, and transcriptional markers of fibrosis (ACTA2) and cholangiocytes (KRT7, KRT19) both at PE and after SPE. SCTR is a promising prognostic marker for PE outcomes and associates with liver injury in BA.

Long-term outcomes of biliary atresia patients surviving with their native livers.

Portoenterostomy (PE) has remained as the generally accepted first line surgical treatment for biliary atresia (BA) for over 50 years. Currently, close to half of BA patients survive beyond 10 years with their native livers, and most of them reach adulthood without liver transplantation (LT). Despite normalization of serum bilirubin by PE, ductular reaction and portal fibrosis persist in the native liver. The chronic cholangiopathy progresses to cirrhosis, complications of portal hypertension, recurrent cholangitis or hepatobiliary tumors necessitating LT later in life. Other common related health problems include impaired bone health, neuromotor development and quality of life. Only few high-quality trials are available for evidence-based guidance of post-PE adjuvant medical therapy or management of the disease complications. Better understanding of the pathophysiological mechanisms connecting native liver injury to clinical outcomes is critical for development of accurate follow-up tools and novel therapies designed to improve native liver function and survival.

Neuropilin-2 Is Associated With Increased Hepatoblastoma Cell Viability and Motility.

The neuropilins NRP1 and NRP2 are multifunctional glycoproteins that have been implicated in several cancer-related processes including cell survival, migration, and invasion in various tumor types. Here, we examine the role of neuropilins in hepatoblastoma (HB), the most common pediatric liver malignancy. Using a combination of immunohistochemistry, RNA analysis and western blotting, we observed high level expression of NRP1 and NRP2 in 19 of 20 HB specimens and in a majority of human HB cell lines (HUH6 and five cell lines established from patient-derived xenografts) studied but not in normal hepatocytes. Silencing of NRP2 expression in HUH6 and HB-282 HB cells resulted in decreased cell viability, impaired cytoskeleton remodeling, and reduced cell motility, suggesting that NRP2 contributes to the malignant phenotype. We propose that neuropilins warrant further investigation as biomarkers of HB and potential therapeutic targets.

Procaspase-Activating Compound-1 Synergizes with TRAIL to Induce Apoptosis in Established Granulosa Cell Tumor Cell Line (KGN) and Explanted Patient Granulosa Cell Tumor Cells In Vitro.

Granulosa cell tumors (GCT) constitute only ~5% of ovarian neoplasms yet have significant consequences, as up to 80% of women with recurrent GCT will die of the disease. This study investigated the effectiveness of procaspase-activating compound 1 (PAC-1), an activator of procaspase-3, in treating adult GCT (AGCT) in combination with selected apoptosis-inducing agents. Sensitivity of the AGCT cell line KGN to these drugs, alone or in combination with PAC-1, was tested using a viability assay. Our results show a wide range in cytotoxic activity among the agents tested. Synergy with PAC-1 was most pronounced, both empirically and by mathematical modelling, when combined with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). This combination showed rapid kinetics of apoptosis induction as determined by caspase-3 activity, and strongly synergistic killing of both KGN as well as patient samples of primary and recurrent AGCT. We have demonstrated that the novel combination of two pro-apoptotic agents, TRAIL and PAC-1, significantly amplified the induction of apoptosis in AGCT cells, warranting further investigation of this combination as a potential therapy for AGCT.

Compromised duodenal mucosal integrity in children with short bowel syndrome after adaptation to enteral autonomy.

BACKGROUND: Intestinal adaptation has been extensively studied experimentally, but very limited data is available on human subjects. In this study we assessed intestinal adaption in humans with short bowel syndrome (SBS). METHODS: We comparatively evaluated mucosal hyperplasia, inflammation, barrier function and nutrient transport using histology, immunohistochemistry and qPCR for selected 52 key genes in duodenal biopsies obtained from children with SBS after weaning off parenteral nutrition (n = 33), and matched controls without intestinal pathology (n = 12). Small bowel dilatation was assessed from contrast small bowel series. RESULTS: Duodenal mucosa of SBS children showed increased histologic inflammation of lamina propria (p = 0.033) and mucosal mRNA expression of tumor necrosis factor (p = 0.027), transforming growth factor (TGF)-ß2 (p = 0.006) and caveolin-1 (CAV1; p = 0.001). Villus height, crypt depth, enterocyte proliferation, apoptosis and expression of proliferation and nutrient transport genes remained unchanged. Pathologic small bowel dilatation reduced crypt depth (p = 0.045) and downregulated mRNA expression of interleukin (IL)-6 by three-fold (p = 0.008), while correlating negatively with IL6 (r = -0.609, p = 0.004). Loss of ileocecal valve (ICV) upregulated mRNA expression of toll-like receptor 4 (TLR4), TGF-ß1, CAV1, several apoptosis regulating genes, and mRNA expression of zonulin (p < 0.05 for all). CONCLUSIONS: Despite successful adaptation to enteral autonomy, duodenal mucosa of SBS children displayed histologic and molecular signs of abnormal inflammation and regulation of epithelial permeability, whereas no structural or molecular signs of adaptive hyperplasia or enhanced nutrient transport were observed. Excessive dilatation of the remaining small bowel paralleled impaired duodenal crypt homeostasis, while absence of ICV modified regulation of mucosal inflammation, regeneration and permeability. LEVEL OF EVIDENCE: II.

Chloroquine Triggers Cell Death and Inhibits PARPs in Cell Models of Aggressive Hepatoblastoma.

Background: Hepatoblastoma (HB) is the most common pediatric liver malignancy. Despite advances in chemotherapeutic regimens and surgical techniques, the survival of patients with advanced HB remains poor, underscoring the need for new therapeutic approaches. Chloroquine (CQ), a drug used to treat malaria and rheumatologic diseases, has been shown to inhibit the growth and survival of various cancer types. We examined the antineoplastic activity of CQ in cell models of aggressive HB. Methods: Seven human HB cell models, all derived from chemoresistant tumors, were cultured as spheroids in the presence of relevant concentrations of CQ. Morphology, viability, and induction of apoptosis were assessed after 48 and 96 h of CQ treatment. Metabolomic analysis and RT-qPCR based Death Pathway Finder array were used to elucidate the molecular mechanisms underlying the CQ effect in a 2-dimensional cell culture format. Quantitative western blotting was performed to validate findings at the protein level. Results: CQ had a significant dose and time dependent effect on HB cell viability both in spheroids and in 2-dimensional cell cultures. Following CQ treatment HB spheroids exhibited increased caspase 3/7 activity indicating the induction of apoptotic cell death. Metabolomic profiling demonstrated significant decreases in the concentrations of NAD+ and aspartate in CQ treated cells. In further investigations, oxidation of NAD+ decreased as consequence of CQ treatment and NAD+/NADH balance shifted toward NADH. Aspartate supplementation rescued cells from CQ induced cell death. Additionally, downregulated expression of PARP1 and PARP2 was observed. Conclusions: CQ treatment inhibits cell survival in cell models of aggressive HB, presumably by perturbing NAD+ levels, impairing aspartate bioavailability, and inhibiting PARP expression. CQ thus holds potential as a new agent in the management of HB.

Predicting native liver injury and survival in biliary atresia.

Several patient and treatment related factors significantly modify outcomes of biliary atresia. The extremely variable prognosis mandates intensive postoperative monitoring following portoenterostomy. Accurate prediction of outcome and progression of liver injury would enable individualized treatment and follow-up protocols, patient counseling and meaningful stratification of patients into clinical trials. While results on most biomarkers of cholestasis, hepatocyte function, fibrosis and inflammation studied so far are inconsistent or have not been validated in independent patient cohorts, postoperative serum bilirubin level 3 months after portoenterostomy remains the most accurate clinically feasible predictor of native liver survival. Although liver stiffness and a novel marker of cholangiocyte integrity, serum matrix metalloproteinase-7, correlate with liver fibrosis and may discriminate biliary atresia from other causes of neonatal cholestasis, further information on their ability to predict portoenterostomy outcomes is needed. Recent gene expression profiling has shown promise in overcoming the sampling error associated with histological quantification of liver fibrosis, and provides an important possibility to stratify patients for clinical trials according to the prognosis of native liver survival already preoperatively. As activity and extent of ductular reaction is linked with progression of liver fibrosis in cholangiopathies, further research is also warranted to evaluate predictive value of ductular reaction, matrix metalloproteinase-7 and the underlying gene expression signatures in relation to circulating bile acids in biliary atresia. Discovery of accurate predictive tools will ultimately increase our understanding of the unpredictable response to surgery and pathophysiology of progressive liver injury in biliary atresia.

Functional Profiling of FSH and Estradiol in Ovarian Granulosa Cell Tumors.

Adult-type granulosa cell tumors (AGCTs) are sex-cord derived neoplasms with a propensity for late relapse. Hormonal modulators have been used empirically in the treatment of recurrent AGCT, albeit with limited success. To provide a more rigorous foundation for hormonal therapy in AGCT, we used a multimodal approach to characterize the expressions of key hormone biomarkers in 175 tumor specimens and 51 serum samples using RNA sequencing, immunohistochemistry, RNA in situ hybridization, quantitative PCR, and circulating biomarker analysis, and correlated these results with clinical data. We show that FSH receptor and estrogen receptor beta (ERß) are highly expressed in the majority of AGCTs, whereas the expressions of estrogen receptor alpha (ERα) and G-protein coupled estrogen receptor 1 are less prominent. ERß protein expression is further increased in recurrent tumors. Aromatase expression levels show high variability between tumors. None of the markers examined served as prognostic biomarkers for progression-free or overall survival. In functional experiments, we assessed the effects of FSH, estradiol (E2), and the aromatase inhibitor letrozole on AGCT cell viability using 2 in vitro models: KGN cells and primary cultures of AGCT cells. FSH increased cell viability in a subset of primary AGCT cells, whereas E2 had no effect on cell viability at physiological concentrations. Letrozole suppressed E2 production in AGCTs; however, it did not impact cell viability. We did not find preclinical evidence to support the clinical use of aromatase inhibitors in AGCT treatment, and thus randomized, prospective clinical studies are needed to clarify the role of hormonal treatments in AGCTs.

The origin of plasma neutrophil gelatinase-associated lipocalin in cardiac surgery.

BACKGROUND: Acute kidney injury (AKI) is common after heart surgery. Neutrophil gelatinase-associated lipocalin (NGAL) is produced in injured kidney. NGAL has been used as an early plasma biomarker for AKI in patients undergoing heart surgery. Neutrophils contain all isoforms (25-kDa, 45-kDa and 145-kDa) but the kidney produces almost exclusively the 25-kDa isoform of NGAL. We investigated first, whether there is association between NGAL and neutrophil activation, and second whether activated neutrophils are a significant source of circulating NGAL in plasma in patients undergoing cardiac surgery. METHODS: Two separate patient cohorts were studied: 1) the "kinetic cohort" (n = 29) and 2) the "FINNAKI cohort" (n = 306). As NGAL is strictly co-localized with lactoferrin in neutrophils, NGAL and lactoferrin were measured with enzyme-linked immunosorbent assay in all patients. In sixty-one patients of the "FINNAKI cohort" Western blot was used to separate NGAL isoforms according to their molecular size. Mann-Whitney U, Kruskal-Wallis H, Pearson's and Spearman's tests were used as appropriate. RESULTS: There was strong intraoperative association between NGAL and lactoferrin at all four time-points in the "kinetic cohort". In the "FINNAKI cohort", NGAL and lactoferrin concentrations correlated preoperatively (R = 0.59, p < 0.001) and at admission to the intensive care unit (R = 0.69, p < 0.001). At admission to intensive care unit, concentrations of NGAL and lactoferrin were higher in AKI than in non-AKI patients (NGAL: p < 0.001; lactoferrin: p < 0.029). In Western blot analyses, neutrophil specific 45-kDa isoform (median 41% [IQR 33.3-53.1]) and mostly neutrophil derived 145-kDa isoform (median 53.5% [IQR 44.0-64.9%]) together represented over 90% of total NGAL in plasma. Potentially kidney derived NGAL isoform (25-kDa) accounted for only 0.9% (IQR 0.3 - 3.0%) of total NGAL in plasma. There were no statistically significant differences in the distribution of NGAL isomers between AKI and non-AKI patients. CONCLUSIONS: Plasma NGAL during cardiac surgery is associated with neutrophil activation. Based on molecular size, the majority of circulating NGAL is derived from neutrophils. Neutrophil activation is a confounding factor when interpreting increased plasma NGAL in cardiac surgery.

Transcription factor GATA4 associates with mesenchymal-like gene expression in human hepatoblastoma cells.

GATA4, a transcription factor crucial for early liver development, has been implicated in the pathophysiology of hepatoblastoma, an embryonal tumor of childhood. However, the molecular and phenotypic consequences of GATA4 expression in hepatoblastoma are not fully understood. We surveyed GATA4 expression in 24 hepatoblastomas using RNA in situ hybridization and immunohistochemistry. RNA interference was used to inhibit GATA4 in human HUH6 hepatoblastoma cells, and changes in cell migration were measured with wound healing and transwell assays. RNA microarray hybridization was performed on control and GATA4 knockdown HUH6 cells, and differentially expressed genes were validated by quantitative polymerase chain reaction or immunostaining. Plasmid transfection was used to overexpress GATA4 in primary human hepatocytes and ensuring changes in gene expression were measured by quantitative polymerase chain reaction. We found that GATA4 expression was high in most hepatoblastomas but weak or negligible in normal hepatocytes. GATA4 gene silencing impaired HUH6 cell migration. We identified 106 differentially expressed genes (72 downregulated, 34 upregulated) in knockdown versus control HUH6 cells. GATA4 silencing altered the expression of genes associated with cytoskeleton organization, cell-to-cell adhesion, and extracellular matrix dynamics (e.g. ADD3, AHNAK, DOCK8, RHOU, MSF, IGFBP1, COL4A2). These changes in gene expression reflected a more epithelial (less malignant) phenotype. Consistent with this notion, there was reduced F-actin stress fiber formation in knockdown HUH6 cells. Forced expression of GATA4 in primary human hepatocytes triggered opposite changes in the expression of genes identified by GATA4 silencing in HUH6 cells. In conclusion, GATA4 is highly expressed in most hepatoblastomas and correlates with a mesenchymal, migratory phenotype of hepatoblastoma cells.

Transcription factor GATA6: a novel marker and putative inducer of ductal metaplasia in biliary atresia.

Biliary atresia (BA), a neonatal liver disease, is characterized by obstruction of extrahepatic bile ducts with subsequent cholestasis, inflammation, and progressive liver fibrosis. To gain insights into the pathophysiology of BA, we focused attention on GATA6, a transcription factor implicated in biliary development. Early in fetal development GATA6 expression is evident in cholangiocytes and hepatocytes, but by late gestation it is extinguished in hepatocytes. Utilizing a unique set of BA liver samples collected before and after successful portoenterostomy (PE), we found that GATA6 expression is markedly upregulated in hepatocytes of patients with BA compared with healthy and cholestatic disease controls. This upregulation is recapitulated in two murine models simulating bile duct obstruction and intrahepatic bile ductule expansion. GATA6 expression in BA livers correlates with two established negative prognostic indicators (age at PE, degree of intrahepatic bile ductule expansion) and decreases after normalization of serum bilirubin by PE. GATA6 expression in BA livers correlates with expression of known regulators of cholangiocyte differentiation ( JAGGED1, HNF1ß, and HNF6). These same genes are upregulated after enforced expression of GATA6 in human hepatocyte cell models. In conclusion, GATA6 is a novel marker and a putative driver of hepatocyte-cholangiocyte metaplasia in BA, and its expression in hepatocytes is downregulated after successful PE. NEW & NOTEWORTHY A pathological hallmark in the liver of patients with biliary atresia is ductular reaction, an expansion of new bile ductules that are thought to arise from conversion of mature hepatocytes. Here, we show that transcription factor GATA6 is a marker and potential driver of hepatocyte ductal metaplasia in biliary atresia. Hepatocyte GATA6 expression is elevated in biliary atresia, correlates with bile duct expansion, and decreases after successful portoenterostomy.

Probing GATA factor function in mouse Leydig cells via testicular injection of adenoviral vectors.

Testicular Leydig cells produce androgens essential for proper male reproductive development and fertility. Here, we describe a new Leydig cell ablation model based on Cre/Lox recombination of mouse Gata4 and Gata6, two genes implicated in the transcriptional regulation of steroidogenesis. The testicular interstitium of adult Gata4flox/flox ; Gata6flox/flox mice was injected with adenoviral vectors encoding Cre + GFP (Ad-Cre-IRES-GFP) or GFP alone (Ad-GFP). The vectors efficiently and selectively transduced Leydig cells, as evidenced by GFP reporter expression. Three days after Ad-Cre-IRES-GFP injection, expression of androgen biosynthetic genes (Hsd3b1, Cyp17a1 and Hsd17b3) was reduced, whereas expression of another Leydig cell marker, Insl3, was unchanged. Six days after Ad-Cre-IRES-GFP treatment, the testicular interstitium was devoid of Leydig cells, and there was a concomitant loss of all Leydig cell markers. Chromatin condensation, nuclear fragmentation, mitochondrial swelling, and other ultrastructural changes were evident in the degenerating Leydig cells. Liquid chromatography-tandem mass spectrometry demonstrated reduced levels of androstenedione and testosterone in testes from mice injected with Ad-Cre-IRES-GFP. Late effects of treatment included testicular atrophy, infertility and the accumulation of lymphoid cells in the testicular interstitium. We conclude that adenoviral-mediated gene delivery is an expeditious way to probe Leydig cell function in vivo Our findings reinforce the notion that GATA factors are key regulators of steroidogenesis and testicular somatic cell survival.Free Finnish abstract: A Finnish translation of this abstract is freely available at http://www.reproduction-online.org/content/154/4/455/suppl/DC2.

Downregulation of transcription factor GATA4 sensitizes human hepatoblastoma cells to doxorubicin-induced apoptosis.

Hepatoblastoma, the most common type of pediatric liver cancer, is treated with a combination of surgery and chemotherapy. An essential drug in the treatment of hepatoblastoma is doxorubicin, which in high doses is cardiotoxic. This adverse effect is due to downregulation of cardiac expression of transcription factor GATA4, leading in turn to diminished levels of anti-apoptotic BCL2 (B-cell lymphoma 2) protein family members. GATA4 is also expressed in early fetal liver, but absent from normal postnatal hepatocytes. However, GATA4 is highly expressed in hepatoblastoma tissue. In this study, we assessed the role of GATA4 in doxorubicin-induced apoptosis of hepatoblastoma cells. Herein, we demonstrate that doxorubicin decreases GATA4 expression and alters the expression pattern of BCL2 family members, most profoundly that of BCL2 and BAK, in the HUH6 hepatoblastoma cell line. Silencing of GATA4 by siRNA prior to doxorubicin treatment sensitizes HUH6 cells to the apoptotic effect of this drug by further shifting the balance of BCL2 family members to the pro-apoptotic direction. Specifically, expression levels of anti-apoptotic BCL2 were decreased and pro-apoptotic BID were increased after GATA4 silencing. On the whole, our results indicate that since high endogenous levels of transcription factor GATA4 likely protect hepatoblastoma cells from doxorubicin-induced apoptosis, these cells can be rendered more sensitive to the drug by downregulation of GATA4.

GLI1+ progenitor cells in the adrenal capsule of the adult mouse give rise to heterotopic gonadal-like tissue.

As certain strains of mice age, hyperplastic lesions resembling gonadal tissue accumulate beneath the adrenal capsule. Gonadectomy (GDX) accelerates this heterotopic differentiation, resulting in the formation of wedge-shaped adrenocortical neoplasms that produce sex steroids. Stem/progenitor cells that reside in the adrenal capsule and retain properties of the adrenogonadal primordium are thought to be the source of this heterotopic tissue. Here, we demonstrate that GLI1+ progenitors in the adrenal capsule give rise to gonadal-like cells that accumulate in the subcapsular region. A tamoxifen-inducible Cre driver (Gli1-creERT2) and two reporters (R26R-lacZ, R26R-confetti) were used to track the fate of GLI1+ cells in the adrenal glands of B6D2F2 mice, a strain that develops both GDX-induced adrenocortical neoplasms and age-dependent subcapsular cell hyperplasia. In gonadectomized B6D2F2 mice GLI1+ progenitors contributed to long-lived adrenal capsule cells and to adrenocortical neoplasms that expressed Gata4 and Foxl2, two prototypical gonadal markers. Pdgfra, a gene expressed in adrenocortical stromal cells, was upregulated in the GDX-induced neoplasms. In aged non-gonadectomized B6D2F2 mice GLI1+ progenitors gave rise to patches of subcapsular cell hyperplasia. Treatment with GANT61, a small-molecule GLI antagonist, attenuated the upregulation of gonadal-like markers (Gata4, Amhr2, Foxl2) in response to GDX. These findings support the premise that GLI1+ progenitor cells in the adrenal capsule of the adult mouse give rise to heterotopic tissue.

Circulating levels of TNF-related apoptosis inducing-ligand are decreased in patients with large adult-type granulosa cell tumors-implications for therapeutic potential.

Targeted treatments are needed for advanced adult-type granulosa cell tumors (AGCTs). We set out to assess tumor tissue and circulating levels of TNF-related apoptosis-inducing ligand (TRAIL), a promising anti-cancer cytokine, in patients affected by AGCT. We analyzed tissue expression of TRAIL in 127 AGCTs using immunohistochemistry or RT-PCR. Soluble TRAIL was measured by means of ELISA from 141 AGCT patient serum samples, as well as the conditioned media of 15 AGCT patient-derived primary cell cultures, and the KGN cell line. Tissue and serum TRAIL levels were analyzed in relationship with clinical parameters, and serum estradiol, FSH, and LH levels. We found that AGCT samples expressed TRAIL mRNA and protein at levels comparable to normal granulosa cells. AGCT cells did not release soluble TRAIL. TRAIL protein levels were decreased in tumors over 10 cm in diameter (p = 0.04). Consistently, circulating TRAIL levels correlated negatively to tumor dimension (p = 0.01). Circulating TRAIL levels negatively associated with serum estradiol levels. In multiple regression analysis, tumor size was an independent factor contributing to the decreased levels of soluble TRAIL in AGCT patients. AGCTs associate with significantly decreased tumor tissue and serum TRAIL levels in patients with a large tumor mass. These findings encourage further study of agonistic TRAIL treatments in patients with advanced or recurrent AGCT.

GATA factors in endocrine neoplasia.

GATA transcription factors are structurally-related zinc finger proteins that recognize the consensus DNA sequence WGATAA (the GATA motif), an essential cis-acting element in the promoters and enhancers of many genes. These transcription factors regulate cell fate specification and differentiation in a wide array of tissues. As demonstrated by genetic analyses of mice and humans, GATA factors play pivotal roles in the development, homeostasis, and function of several endocrine organs including the adrenal cortex, ovary, pancreas, parathyroid, pituitary, and testis. Additionally, GATA factors have been shown to be mutated, overexpressed, or underexpressed in a variety of endocrine tumors (e.g., adrenocortical neoplasms, parathyroid tumors, pituitary adenomas, and sex cord stromal tumors). Emerging evidence suggests that GATA factors play a direct role in the initiation, proliferation, or propagation of certain endocrine tumors via modulation of key developmental signaling pathways implicated in oncogenesis, such as the WNT/ß-catenin and TGFß pathways. Altered expression or function of GATA factors can also affect the metabolism, ploidy, and invasiveness of tumor cells. This article provides an overview of the role of GATA factors in endocrine neoplasms. Relevant animal models are highlighted.