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Background 20(S)-protopanaxadiol (20(S)-PPD), one of the main active metabolites of ginseng, performs a broad spectrum of anti-tumor effects. Our aims are to search out new strategies to enhance anti-tumor effects of natural products, including 20(S)-PPD. In recent years, fasting has been shown to be multi-functional on tumor progression. Here, the effects of fasting combined with 20(S)-PPD on hepatocellular carcinoma growth, apoptosis, migration, invasion and cell cycle were explored. Methods CCK-8 assay, trypan blue dye exclusion test, imagings photographed by HoloMonitorTM M4, transwell assay and flow cytometry assay were performed for functional analyses on cell proliferation, morphology, migration, invasion, apoptosis, necrosis and cell cycle. The expressions of genes on protein levels were tested by western blot. Tumor-bearing mice were used to evaluate the effects of intermittent fasting combined with 20(S)-PPD. Results We firstly confirmed that fasting-mimicking increased the anti-proliferation effect of 20(S)-PPD in human HepG2 cells in vitro. In fasting-mimicking culturing medium, the apoptosis and necrosis induced by 20(S)-PPD increased and more cells were arrested at G0-G1 phase. Meanwhile, invasion and migration of cells were decreased by down-regulating the expressions of matrix metalloproteinase (MMP)-2 and MMP-9 in fasting-mimicking medium. Furthermore, the in vivo study confirmed that intermittent fasting enhanced the tumor growth inhibition of 20(S)-PPD in H22 tumor-bearing mice without obvious side effects. Conclusion Fasting significantly sensitized HCC cells to 20(S)-PPD in vivo and in vitro. These data indicated that dietary restriction can be one of the potential strategies of chinese medicine or its active metabolites against hepatocellular carcinoma., Graphical abstract Image 1

Huganpian (HGP), a traditional chinese medicine composed of 6 herbs, possesses excellent therapeutic effects in clinical application. In this study, we aimed to elucidate the anti-tumor activity and the underlying mechanisms of HGP in liver cancer. The results of this study indicated that HGP effectively inhibited liver cancer growth in vitro and in vivo in a dose-dependent manner. Mechanistically, HGP exerted its anti-tumor effects by triggering autophagy with increased LC3Ⅱ and beclin1 levels and arrested the cell cycle on G0-G1 phase by downregulating the expressions of cyclin-dependent kinase 2 (CDK2), cyclin-dependent kinase 4 (CDK4) and cyclinE1 in vitro and in vivo. Meanwhile, HGP did not induce apoptosis significantly. Importantly, we also confirmed that there were fewer side effects of HGP on immune system. Taken together, our findings suggest for the first time that HGP may become a promising drug or adjuvant drug with a lower toxicity for liver cancer treatment in the future.

Nucleotides are important players in intercellular signaling communication network. P2X family receptors (P2XRs) are ATP-gated plasma membrane ion channels with diverse biological functions. Macrophages are important components in the microenvironment of hematopoiesis participating in both physiological and pathological processes. However, the role of P2XRs in macrophages in leukemia has not been established. Here we investigated expression pattern and functions of P2XRs in macrophages from bone marrow (BM) and spleen of Notch1-induced T-ALL mice. Real-time PCR showed that P2XRs except P2X5R were expressed in BM and spleen macrophages. Furthermore, with the development of leukemia, the expression of P2X7R increased in both BM and spleen macrophages whereas expression of P2X1R increased in spleen macrophages. Live cell imaging recoding the Ca(2+) response demonstrated that P2X7R expressed in macrophages was functional. TUNEL and electron microscopy analysis found that apoptotic macrophages were frequently observed in BM and spleen at late stage of leukemia, which was partly contributed by the activation of overexpressed P2X7R. Our results suggested that the intercellular communication mediated by nucleotides might orchestrate in the pathological process of leukemia and could be a potential target for the treatment of leukemia.

Fbxw11, as a member of F-box proteins family, is a constituent of the SCF (Skp1-Cul1-F box) ubiquitin ligase complex. This ligase ubiquitinates specifically phosphorylated substrates and controls the degradation and half-life of key cellular regulators. So, Fbxw11 play a pivotal role in many aspects of hematopoiesis and tumorigenesis through regulating various signal transduction pathways. We found two transcript variants (Fbxw11c and Fbxw11d) in mouse bone marrow. However the role of Fbxw11 variants in the development of leukemia and the underlying mechanisms remain largely unknown. In this study, we cloned three transcript variants (Fbxw11a, Fbxw11c and Fbxw11d) to study the biological function of Fbxw11 in leukemia. In order to investigate the role of Fbxw11 variants in leukemia, we established L1210 cell lines with over-expression of Fbxw11a, Fbxw11c and Fbxw11d respectively using the lentivirus system. The effect of Fbxw11 variants on proliferation of leukemia cells in vitro was first detected. Growth curve of leukemia cells with Fbxw11a, Fbxw11c or Fbxw11d over-expression was established by cell counting. The results suggested that over-expression of Fbxw11 variants stimulated the growth of leukemia cells. Then MTT experiment was carried out to study the effect of Fbxw11 variants on leukemia cell proliferation and the results showed that Fbxw11 variants increased the proliferation of L1210 cells in vitro. To further confirm the effects of Fbxw11 variants on proliferation of leukemia cells in vivo, tumor xenografts model with over-expression of Fbxw11a, Fbxw11c and Fbxw11d in DBA/2 mice was established. Leukemia cells L1210 with over-expression of Fbxw11a, Fbxw11c and Fbxw11d respectively were transplanted into DBA/2 mice by hypodermic injection. The tumor growth curves showed that tumor growth was increased in Fbxw11 variants over-expression group compared to the control group. Mice were sacrificed on day 28 after transplantation, greater volume of the xenograft tumors were obtained from Fbxw11 variants over-expression group than control group. Therefore, Over-expression of Fbxw11 variants could increase growth of tumor in vivo. To further investigate the molecular mechanism under the effect of Fbxw11 variants on proliferation of leukemia cells, we tested the apoptosis and cell cycle of leukemia cells with Fbxw11 variants over-expression. Over-expression of Fbxw11 variants did not affect the cell apoptosis but accelerated the process of cell cycle. These results revealed that the increased cell proliferation was not due to decrease in cell apoptosis but due to increase in cell cycle. In addition, we tested the effect of Fbxw11 variants on the signal transduction by dual-luciferase reporter gene system. The results showed that over-expression of Fbxw11 variants caused the activation of NF-κB signaling pathway. In conclusion, our findings suggest that Fbxw11 variants have promoting effect on cell proliferation of leukemia cells. The effect of Fbxw11 variants on cell proliferation are due to accelerated the process of cell cycle but not decreasing in cell apoptosis. Further study demonstrated that Fbxw11 variants promote cell proliferation through activating the NF-κB signaling pathway. The important role of Fbxw11 in regulating the development of leukemia suggests that a potent rationale for developing Fbxw11 as a potential therapeutic target against leukemia. Disclosures No relevant conflicts of interest to declare.

F-box proteins serve as the substrate recognition subunit for the SCF E3 ubiquitin ligases. These ligases ubiquitinate specifically phosphorylated substrates and play a pivotal role in the regulation of various signal transduction pathways, which, in turn, are essential for many aspects of tumorigenesis. However the role of Fbxw11 in the development of leukemia and the underlying mechanisms remain largely unknown. Here, we found two transcript variants (Fbxw11c and Fbxw11d) expressed in mouse bone marrow. More importantly, the expression of Fbxw11 in normal hematopoietic stem cells (HSCs) from Notch1-induced leukemia mice was higher than that from control mice. In order to investigate the role of Fbxw11 in leukemia, we established L1210 cell lines over-expressing Fbxw11c or Fbxw11d respectively using the lentivirus system. Over-expression of both Fbxw11 variants stimulated the proliferation of L1210 cells in vitro by cell counting and MTT assay. The tumor xenografts model with over-expression of Fbxw11c or Fbxw11d in DBA/2 mice was further established. Over-expression of both variants resulted in the increased tumor growth in vivo. Investigation of the molecular mechanism revealed that the increased cell proliferation was not due to decrease in cell apoptosis but due to increase in cell cycle. Further studies showed that overexpression of both Fbxw11c and Fbxw11d caused the activation of NF-κB signaling pathway. These findings suggest the important role of Fbxw11 in regulating the development of leukemia and indicate a potent rationale for developing Fbxw11 as a potential therapeutic target against leukemia. Citation Format: Lina Wang, Jinfeng Liao, Xiao Yang, Wenli Feng, Shayan Chen, Guoguang Zheng. Fbxw11 promotes leukemia development by activating the NF-κB signaling pathway. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4433. doi:10.1158/1538-7445.AM2014-4433