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Xanthohumol (XN), a prenylflavonoid found in the hop plant, Humulus lupulus, exhibits a variety of biological activities. Numerous studies have reported that XN inhibits the growth of many types of cancer cells, but the effects of XN on tumor immunity have not yet been studied. We explored the effect of XN on Th1/Th2 balance and the underlying mechanism based on a BALB/c-4T1 breast cancer mouse model. The results showed that XN significantly slowed down tumor growth and inhibited expression of antitumor proliferation protein Ki-67 as well as breast cancer-specific marker cancer antigen 15-3 (CA15-3). Flow cytometric analysis revealed that XN enhanced the secretion of perforin, granzyme B and increased the ratio of CD8+/CD25+. ELISA analysis of cytokine results demonstrated that XN obviously upregulated Th1 cytokines, while downregulated Th2 cytokines. Th1/Th2 ratio analysis by flow cytometry illustrated that XN regulated the balance drift to Th1 polarization. Western blotting and immunohistochemistry (IHC) results manifested that XN induced expression of T-bet, a Th1-specific transcription factor. Furthermore, we found that XN significantly promoted the phosphorylation of signal transducer and activator of transcription (STAT)4. Our results demonstrated that XN promoted Th1/Th2 balance towards Th1 polarization, and STAT4 may play a positive role in the regulation of Th1/Th2 cytokines by XN.

Etoposide is a semi-synthetic glycoside derivative of podophyllotoxin, also known as VP-16. It is a widely used anticancer medicine in clinics. Unfortunately, high doses or long-term etoposide treatment can induce therapy-related leukemia. The mechanism by which etoposide induces secondary hematopoietic malignancies is still unclear. In this article, we review the potential mechanisms of etoposide induced therapy-related leukemia. Etoposide related leukemogenesis is known to depend on reactive oxidative metabolites of etoposide, notably etoposide quinone, which interacts with cellular proteins such as topoisomerases II (TOP2), CREB-binding protein (CREBBP), and T-Cell Protein Tyrosine Phosphatase (TCPTP). CYP3A4 and CYP3A5 metabolize etoposide to etoposide catechol, which readily oxidizes to etoposide quinone. As a poison of TOP2 enzymes, etoposide and its metabolites induce DNA double-stranded breaks (DSB), and the accumulation of DSB triggers cell apoptosis. If the cell survives, the DSB gives rise to the likelihood of faulty DNA repair events. The gene translocation could occur in mixed-lineage leukemia ( MLL ) gene, which is well-known in leukemogenesis. Recently, studies have revealed that etoposide metabolites, especially etoposide quinone, can covalently bind to cysteines residues of CREBBP and TCPTP enzymes, . This leads to enzyme inhibition and further affects histone acetylation and phosphorylation of the JAK-STAT pathway, thus putatively altering the proliferation and differentiation of hematopoietic stem cells (HSC). In brief, current studies suggest that etoposide and its metabolites contribute to etoposide therapy-related leukemia through TOP2 mediated DSB and impairs specific enzyme activity, such as CREBBP and TCPTP.

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Introduction: Targeted drugs are needed for HR-MDS/AML, particularly in elderly patients and Venetoclax, approved for some CLL, gives promising results in elderly AML. Assays to predict response to treatment may enable us to deliver personalized treatment. We sought to determine the most informative assay to predict response; viability assays can directly measure the effects of reagents on growth. Progenitor assays can potentially determine if the reagents can target diseased primitive cells. PET scanning can be used to follow response to treatment. Methods: Peripheral blood (PB) or bone marrow (BM) from 7 MDS/AML patients were incubated in a) no treatment, b) ABT-199 (1 µM) (Abbvie), c) GDC-0973 (1 µM) (Genentech) or d) ABT-199+GDC-0973 (1 µM of each) and assessed for viability using the MTT assay (n=2); cell death followed using the Incucyte® Zoom System (Essen Bioscience) (n=2) or methocult progenitor assays (Stem Cell Technologies) (n=4). Having shown that RAS:BCL-2 co-localization correlated with prognosis in MDS/AML patients (Leuk Res 37:312-9, 2013), immunofluorescence was undertaken. A micro PET device dedicated to mice was used to measure BM blast proliferation. After injection of 18F-FLT(a thymidine analogue) in mice untreated (n=7) or ABT-199 (75mg/kg)+GDC-0973(10mg/kg) treated (n=5) normal FVB/N, HR-MDS mice treated with vehicle (n=4), 2-month old HR-MDS before (n=5) and 3-month old before (n=4) and after ABT-199 (75mg/kg)+GDC-0973(10mg/kg) treatment (n=8), PET imaging was performed (Inveon Siemens Medical Systems), analyzed for signal and quantified. Results: Patient details and results are summarized on Table 1. Using the MTT assay 2 PB patient samples were found to be sensitive to ABT-199 treatment (Figure 1A, AS, p=0.00042 and YA, 0.00002) and more sensitive to the combination compared to untreated (AS, p=0.00007 and YA, 0.000003). With the incucyte the BM of one patient (AE) was found to be resistant to both ABT-199 and GDC-0973, but sensitive to the combination (Figure 1B). PB and BM from patient JA were assayed for apoptosis with the incucyte and were found to be sensitive to ABT-199 with increased apoptosis, resistant to GDC-0973 with decreased apoptosis and sensitive to the combination. Four bone marrow samples were tested in the 4 conditions using the progenitor assay (Figure 1C). Three patients were sensitive to GDC-0973, inhibiting any colony formation and the fourth had reduced colony numbers. In this assay patient JA appeared to be sensitive to GDC-0973 treatment whereas the incucyte assay scored this sample to be resistant to apoptosis; thus the cytotoxic effects of GDC-0973 may not be via apoptopsis. As the progenitor assay is likely to score the primitive disease population, this assay may prove more informative than the others without prior selection. One patient (DH) was clearly resistant to ABT-199, whereas the other three (JA, CB and FL) had reduced colony growth. All patients were sensitive to the combination treatment and inhibited colony growth. The RAS:BCL-2 co-localization in the PB revealed no complex in either the Mito or PM upon treatment with ABT-199 alone and some localization in the Mito with GDC-0973. With both ABT-199 and GDC-0973, there were hardly any cells confirming the cytotoxic effects of the combination. As we have previously shown that PM co-localization of the complex is associated with drug resistance (Blood 130:2613, 2017Suppl), we used the combination on our HR-MDS mouse model, where the complex co-localizes in the PM and followed the mice by PET scanning (Figure 1D). Weak signal was visualized in the femurs of untreated and ABT-199+GDC-0973 treated FVB/N mice (FBR 1.17+/-0.34 and 1.02+/-0.08 respectively). Mild PET signal was seen in the femurs of 2 month-old HR-MDS mice, (FBR 1.79+/-0.98). Intense PET signal was seen in the femurs and proximal humerus of HR-MDS mice treated with vehicle (3 month-old, FBR=2.35+/-1.32). Low PET signals were seen in the femurs of 5/8 HR-MDS mice treated with ABT-199+GDC-0973 (FBR=1.93+/-0.84). FBRs of the 3 groups of HR-MDS mice were significantly higher than those of FBV/N groups. Conclusion: Combined Venetoclax (ABT-199) and GDC-0973 targets MDS/AML progenitors and can potentially overcome drug resistance with the disruption of the RAS:BCL-2 complex. Bone marrow disease progression in HR-MDS mice can be monitored with 18F-FLT-PET imaging; PET data shows that the combination slows down disease progression. Disclosures Padua: Abbvie: Research Funding; Genentech: Research Funding. Giraudier:Novartis: Research Funding. Konopleva:Stemline Therapeutics: Research Funding. Andreeff:Oncoceutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; United Therapeutics: Patents & Royalties: GD2 inhibition in breast cancer ; Reata: Equity Ownership; Celgene: Consultancy; Jazz Pharma: Consultancy; Oncolyze: Equity Ownership; Amgen: Consultancy, Research Funding; Eutropics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Aptose: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Daiichi-Sankyo: Consultancy, Patents & Royalties: MDM2 inhibitor activity patent, Research Funding; SentiBio: Equity Ownership; Astra Zeneca: Research Funding.

Myeloproliferative neoplasms (MPN) are a group of blood cancers in which the bone marrow (BM) produces an overabundance of erythrocyte, white blood cells, or platelets. Philadelphia chromosome-negative MPN has three subtypes, including polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). The over proliferation of blood cells is often associated with somatic mutations, such as JAK2, CALR, and MPL. JAK2V617F is present in 95% of PV and 50–60% of ET and PMF. Based on current molecular dynamics simulations of full JAK2 and the crystal structure of individual domains, it suggests that JAK2 maintains basal activity through self-inhibition, whereas other domains and linkers directly/indirectly enhance this self-inhibited state. Nevertheless, the JAK2V617F mutation is not the only determinant of MPN phenotype, as many normal individuals carry the JAK2V617F mutation without a disease phenotype. Here we review the major MPN phenotypes, JAK-STAT pathways, and mechanisms of development based on structural biology, while also describing the impact of other contributing factors such as gene mutation allele burden, JAK-STAT-related signaling pathways, epigenetic modifications, immune responses, and lifestyle on different MPN phenotypes. The cross-linking of these elements constitutes a complex network of interactions and generates differences in individual and cellular contexts that determine the phenotypic development of MPN.

The aim of this study is to identify the role of Tet1-mediated DNA demethylation in the neurotoxicity caused by unconjugated bilirubin (UCB) in vitro. Primary neuronal cells after cultured for 72 h were exposed to UCB (0-100 μmol/L) for 24 h. Following exposure to UCB cytotoxicity was determined with the methyl tetrazolium (MTT) assay, reactive oxygen species (ROS) and caspase-3 activity in neuron cells were measured with the corresponding assay kits. The expression of Tet1 and Klotho was determined with RT-PCR at mRNA level and western blot at protein level. Our results showed that UCB can cause time-dependent and dose-dependent reduction of cell viability of neuronal cells, induce oxidative stress through increasing the production of ROS and increase caspase-3 activity. Quantitative real-time PCR and western blot analysis showed that UCB can inhibit Tet1 and Klotho expression in cultured neuronal cells at both the mRNA and protein level, respectively. These results are first to suggest UCB may, in part, exert its neurotoxicity through alteration of the neuronal antioxidant status and inhibition of Klotho and Tet1 gene expression. The elevation of DNA methylation in global genome through inhibition of Tet1 gene expression may, in part, play an important role in the neurotoxicity caused by UCB in vitro.

Immune system is critical to protecting human health from toxic substances. Our previously published research had found an important link between polycyclic aromatic hydrocarbons (PAHs) in ambient air and changes at the DNA level in immune cells that led to impaired function of regulatory T (Treg) cells in children living in California, USA. But molecular and cellular pathways of these changes remain unclear. The present study aims to explore whether exposure to PAHs leads to changes in Treg cells functions of children living in Gansu, China, where ambient air pollution levels are much higher than those in California, and to explore potential mechanisms of PAH-induced immunological dysfunctions. Air pollutions in Lanzhou and Lintao, Gansu Province, were measured from December 2015 to June 2016. Healthy children were recruited from both cities and enrolled in this pilot study. Demographic information was collected by questionnaires. Blood samples were collected. Peripheral blood Treg cells were analyzed for Treg cells percentage by flow cytometry. Gene expression of forkhead box transcription factor 3 (Foxp3), transforming growth factor-β (TGF-β), and interleukin 35 (IL35) were examined by reverse transcription-polymerase chain reaction (RT-PCR). The results indicated PAH concentration (as sum of 16 PAHs) in Lintao was over two times higher than that was in Lanzhou (707 vs. 326 ng/m), whereas PM concentration was comparable in two cities (55.3 in Lintao vs. 65.7 μg/m in Lanzhou). Notably, we observed lower gene expressions for Foxp3 (P < 0.05), IL35 (P < 0.05), and TGF-β, in children living in Lintao, suggesting an impairment of Treg cells function potentially associated with higher PAH exposure in Lintao. However, no significant difference was observed in Treg cells % among CD4 T cells between Lanzhou and Lintao groups.