Therapeutic Innovations for Targeting Hepatoblastoma.

Hepatoblastoma is the most common pediatric liver tumor. Despite recent advances in treatment with surgery and chemotherapy, the prognosis in advanced stages remains poor. The neurokinin-1 receptor (NK1R) has recently been described to be pivotal in the development of cancer. Furthermore, overwhelming evidence now exists showing that pharmacological manipulation of NK1R can cause a robust anticancer effect. Consequently, NK1R antagonists, such as the clinical drug aprepitant, are under current investigation as future innovative anticancer agents. In that sense, new evidence suggests that NK1R is highly expressed in human hepatoblastoma and can be targeted to create a robust inhibiton of tumor growth in vivo and in vitro. The mechanisms behind this effect are only now being investigated but already reveal an arsenal of therapeutic possibilities. Our article describes the most recent developments in the field of therapeutic NK1R inhibition in cancer and focuses particularly on the newly discovered molecular mechanisms involved when targeting NK1R in hepatoblastoma.

Truncated neurokinin-1 receptor is an ubiquitous antitumor target in hepatoblastoma, and its expression is independent of tumor biology and stage.

The substance P (SP; also known as TAC1)/neurokinin-1 receptor (NK1R; also known as TACR1) complex is a critical part in the development of cancer. Therefore, NK1R antagonists, such as the clinical drug aprepitant, are currently under investigation as future anticancer agents. In a previous study, NK1R (TACR1) was identified as a potent anticancer target in hepatoblastoma (HB). However, little is known regarding the exact distribution of this target among HB subsets and whether it correlates with clinical features and prognosis. In the present study, mRNA was isolated from 47 children with HB, and reverse transcription-quantitative polymerase chain reaction was performed on the samples to analyze the expression of full-length-TACR1 (fl-TACR1) and truncated-TACR1 (tr-TACR1). These data were correlated with data obtained from 9 tumor-free controls, as well as with the presence of metastasis, PRETEXT, vascular invasion, histology, age of diagnosis, multifocality, CTNNB1 mutation, gender and overall survival. Additionally, the present study investigated a recently described 16-gene signature characterizing HB known to correlate with prognosis. Compared with tumor-free liver tissue, tumorous tissue expressed TACR1 significantly higher for the truncated version (P=0.0301), and by trend also for the full-length version. Accordingly, the expression of fl-TACR1 correlated with the expression of the truncated version (P=0.0074). Furthermore, a low expression of fl-TACR1 correlated with characteristics of the 16-gene signature known to predict prognosis (P=0.0222). However, there was no correlation between tr-TACR1 and the tumor characteristics investigated, including outcome, although a clear trend was observed for some tumor characteristics. The current results reinforced the previously described findings that in HB, tr-TACR1 is overexpressed compared with tumor-free liver tissue. Furthermore, to the best of our knowledge, the present study demonstrated for the first time that tr-TACR1 is expressed ubiquitously among the different subsets of HB. Therefore, NK1R may serve as a potent anticancer target in a large variety of patients with HB, independent of tumor biology and clinical stage.

VIP and PACAP analogs regulate therapeutic targets in high-risk neuroblastoma cells.

Neuroblastoma (NB) is a pediatric cancer. New therapies for high-risk NB aim to induce cell differentiation and to inhibit MYCN and ALK signaling in NB. The vasoactive intestinal peptide (VIP) and the pituitary adenylate cyclase-activating polypeptide (PACAP) are 2 related neuropeptides sharing common receptors. The level of VIP increases with NB differentiation. Here, the effects of VIP and PACAP analogs developed for therapeutic use were studied in MYCN-amplified NB SK-N-DZ and IMR-32 cells and in Kelly cells that in addition present the F1174L ALK mutation. As previously reported by our group in IMR-32 cells, VIP induced neuritogenesis in SK-N-DZ and Kelly cells and reduced MYCN expression in Kelly but not in SK-N-DZ cells. VIP decreased AKT activity in the ALK-mutated Kelly cells. These effects were PKA-dependent. IMR-32, SK-NDZ and Kelly cells expressed the genes encoding the 3 subtypes of VIP and PACAP receptors, VPAC1, VPAC2 and PAC1. In parallel to its effect on MYCN expression, VIP inhibited invasion in IMR-32 and Kelly cells. Among the 3 PACAP analogs tested, [Hyp(2)]PACAP-27 showed higher efficiency than VIP in Kelly cells. These results indicate that VIP and PACAP analogs act on molecular and cellular processes that could reduce aggressiveness of high-risk NB.

Targeting the Neurokinin-1 Receptor Compromises Canonical Wnt Signaling in Hepatoblastoma.

The substance P (SP)/NK-1 receptor (NK1R) complex represents an intriguing anticancer target for a variety of tumors, including hepatoblastoma (HB). Therefore, NK1R antagonists, such as the clinical drug aprepitant, recently have been proposed as potent anticancer agents. However, very little is known regarding the molecular basis of NK1R inhibition in cancer. Using reverse phase protein array, Western blot, Super TOP/FOP, confocal microscopy, and sphere formation ability (SFA) assays, we identified the AKT and Wnt signaling pathways as the key targets of aprepitant in three human HB cell lines (HepT1, HepG2, and HuH6). Following NK1R blockage, we observed decreased phosphorylation of p70S6K and 4E-BP1/2 and inhibition of the canonical Wnt pathway with subsequent decrease of HB cell growth. This effect was dependent of high baseline Wnt activity either by mutational status of ß-catenin or extrinsic Wnt activation. Wnt inhibition seemed to be strengthened by disruption of the FOXM1-ß-catenin complex. Furthermore, treatment of HB cells with aprepitant led to reduced expression of (liver) stemness markers (AFP, CD13, SOX2, NANOG, and OCT4) and SFA when grown under cancer stem cell conditions. Taken together, we show for the first time that targeting the SP/NK1R signaling cascade inhibits canonical Wnt signaling in HB cells. These findings reveal important insight into the molecular mechanisms of the SP/NK1R complex as a critical component in a model of pediatric liver cancer and may support the development of novel therapeutic interventions for HB and other Wnt-activated cancers.

Secretory Breast Carcinoma: A Histopathologic and Genomic Spectrum Characterized by a Joint Specific ETV6-NTRK3 Gene Fusion.

Secretory breast carcinoma (SBC) is a rare breast carcinoma with distinctive morphologic features and a recurrent specific chromosomal translocation t(12;15)(p13;q25), usually of low histologic grade and favorable prognosis. We describe the morphologic and genetic characteristics of 11 cases of SBC from 10 patients. Histologic and immunohistochemical analyses, fluorescence in situ hybridization using break-apart probes specific to ETV6 on 12p13, reverse transcription polymerase chain reaction with in-house probes specific to the ETV6-NTRK3 gene fusion, and DNA copy number variation by array comparative genomic hybridization analyses were performed on all cases. Seven cases were of low histologic grade, 3 were intermediate, and 1 had high-grade nuclear atypia, necrosis, and numerous mitoses. This patient had a fatal outcome. Five cases displayed low hormonal receptor expression, whereas the rest had basal-type immunoprofiles. All interpretable cases harbored an ETV6-NTRK3 gene fusion by reverse transcription polymerase chain reaction and/or an ETV6 rearrangement by fluorescence in situ hybridization, with duplication of the oncogenic derivative in 2 cases. Array comparative genomic hybridization analysis showed simplex genomic profiles. The 2 cases with ETV6-NTRK3 duplication included a gain of 12p starting from the ETV6 locus to the telomere, associated with a gain of the 15q from the centromere to NTRK3 in 1 case, and in the other a normal profile up to NTRK3 on 15q, and then a loss up to the telomere, suggesting loss of corresponding normal chromosome 15. These findings provide a novel insight into the morphologic and genetic spectrum of SBC, ranging from low-grade to high-grade histology, with occasional low hormonal receptor expression, simplex genomic profiles, and possible unfavorable course.

Targeting the neurokinin-1 receptor inhibits growth of human colon cancer cells.

The substance P (SP)/neurokinin-1 receptor (NK1R) complex and the Wnt cascade are pivotal signaling pathways in the regulation of cell growth and hence, potent targets for future anticancer therapies. However, while the Wnt cascade has long been associated with colon cancer, little is known about the expression of the NK1R complex as a potential target in this tumor and its molecular basis in tumorigenesis in general. We treated the human colon cancer cell lines LiM6 and DLD1 with the NK1R antagonist and the clinical drug aprepitant (AP) and analyzed both growth response and downstream mechanisms using MTT-assay, reverse phase protein array (RPPA), western blot, Super TOP/FOP, confocal microscopy, and sphere formation ability (SFA) assays. Following NK1R blockage, we found significant growth inhibition of both colon cancer cell lines. When analyzing downstream mechanisms, we found a striking inhibition of the canonical Wnt pathway represented by decreased Super TOP/FOP and increased membrane stabilization of ß-catenin. This effect was independent from baseline Wnt activity and mutational status of ß-catenin. Further, treatment of colon cancer cells grown under cancer stem cell (CSC) conditions reduced sphere formation in both number and size after a single treatment period. We show that the NK1R can be a potent anticancer target in colon cancer and that NK1R antagonists could potentially serve as future anticancer drugs. This effect was seen not only in primary cancer cells but, for the first time, also in CSC-like cells, potentially including these cells in a therapeutic effect. Also, we describe the robust inhibition of canonical Wnt signaling through targeting the SP/NK1R signaling cascade. These findings give important insight into the molecular mechanisms of the SP/NK1R complex as a critical component in tumorigenesis and could help to identify future anticancer therapies for colon and other Wnt-activated cancers.

Hepatoblastoma cells express truncated neurokinin-1 receptor and can be growth inhibited by aprepitant in vitro and in vivo.

BACKGROUND & AIMS: Multidrug resistance presents a major problem in hepatoblastoma (HB), and new anti-tumor strategies are desperately needed. The substance P (SP)/neurokinin-1 receptor (NK1R) complex has been discovered to be pivotal in the development of a variety of human cancers, and NK1R antagonists, such as the clinical drug aprepitant, are promising future anticancer agents. Yet, the role of the SP/NK1R complex as a potential anticancer target in HB is unknown. METHODS: Human HB cell lines HepT1, HepG2, and HuH6, human tumor samples from 17 children with HB as well as mice xenografted with human HB cell line HuH6 were analyzed regarding the SP/NK1R complex as a potential new anti-tumor target in HB. RESULTS: Therapeutic targeting with the NK1R antagonists aprepitant, L-733,060, and L-732,138 led to growth inhibition and apoptosis in HepT1, HepG2, and HuH6 cells in a dose-dependent manner. Intriguingly, HB cells predominantly expressed the truncated splice variant of NK1R. Human fibroblasts showed only dismal NK1R expression and were significantly more resistant. Stimulation of HB cells with SP, NK1R's natural ligand, caused increased growth rates and abrogated the anti-proliferative effect of NK1R antagonists. Expression analysis of 17 human HB samples confirmed the clinical relevance of NK1R. Most importantly, oral treatment of a HuH6 xenograft mouse model with 80mg/kg/day aprepitant for 24days resulted in a striking reduction of tumor growth, as evidenced by reduced tumor volume and weight, lowered tumor-specific alpha-fetoprotein (AFP) serum levels, and decreased number of Ki-67 positive cells. Furthermore, aprepitant treatment inhibited in vivo angiogenesis. CONCLUSIONS: For the first time, we describe the NK1R in its truncated splice variant as a potent target in human HB and an inhibitory effect in vivo and in vitro by NK1R antagonists. Therefore, NK1R antagonists should be considered promising new candidates for innovative therapeutic strategies against HB.

Investigation of hydrogenation of toluene to methylcyclohexane in a trickle bed reactor by low-field nuclear magnetic resonance spectroscopy.

Low-field nuclear magnetic resonance (NMR) spectroscopy is applied to study the hydrogenation of toluene in a lab-scale reactor. A conventional benchtop NMR system was modified to achieve chemical shift resolution. After an off-line validity check of the approach, the reaction product is analyzed on-line during the process, applying chemometric data processing. The conversion of toluene to methylcyclohexane is compared with off-line gas chromatographic analysis. Both classic analytical and chemometric data processing was applied. As the results, which are obtained within a few tens of seconds, are equivalent within the experimental accuracy of both methods, low-field NMR spectroscopy was shown to provide an analytical tool for reaction characterization and immediate feedback.

Determination of porosity and flow distribution in packed beds by magnetic resonance imaging.

Magnetic resonance methods have been used to investigate the porosity and flow distributions in packed beds. The motivation of our study is to understand the behaviour of multiphase flow in fixed bed reactors, especially in trickle bed reactors. The results of this study should be included in a model for predicting the influence of hydrodynamics on hydrodesulfurization process in bench-scale reactors.