葛根素经p53/GLIPR1途径调节膀胱癌UMUC-3细胞增殖及侵袭的机制研究

目的:探讨葛根素经p53/GLIPR1途径调节膀胱癌UMUC-3细胞增殖及侵袭的机制。方法:设膀胱癌UMUC-3细胞组、氟尿嘧啶组(80.0μg·ml^-1)、葛根素低、高剂量组(剂量分别为60.0μg·ml^-1、120.0μg·ml^-1),置于CO2培养箱(37℃、5%CO2、2%O2、93%N2)培养72 h。细胞培养结束后,测定各组UMUC-3细胞增殖水平、侵袭能力、凋亡率水平以及p53、GLIPR1基因蛋白水平。结果:氟尿嘧啶组、葛根素低、高剂量组吸光度(A)值、存活率水平、克隆形成数目、穿膜数、p53 m RNA、蛋白水平低于UMUC-3细胞组(P<0.05),凋亡率、GLIPR1 m RNA、蛋白水平高于UMUC-3细胞组(P<0.05);葛根素低剂量组A值、存活率水平、克隆形成数目、穿膜数、p53 m RNA、蛋白水平高于氟尿嘧啶组(P<0.05),凋亡率、GLIPR1 m RNA、蛋白水平低于氟尿嘧啶组(P<0.05);葛根素高剂量组A值、存活率水平、克隆形成数目、穿膜数、p53 m RNA、蛋白水平低于氟尿嘧啶组(P<0.05),凋亡率、GLIPR1 m RNA、蛋白水平高于氟尿嘧啶组(P<0.05)。结论:葛根素通过抑制p53 m RNA、蛋白的表达,促进GLIPR1 m RNA、蛋白的表达进而抑制膀胱癌细胞的增殖及侵袭,促进膀胱癌细胞的凋亡。

Pien Tze Huang Inhibits Proliferation of Colorectal Cancer Cells through Suppressing PNO1 Expression and Activating p53/p21 Signaling Pathway

ObjectiveTo explore the regulatory effect of Pien Tze Huang (PZH) on targeting partner of NOB1 (PNO1) and it’s down-stream mediators in colorectal cancer (CRC) cells.MethodsQuantitative polymerase chain reaction was performed to determine mRNA levels of PNO1, TP53, and CDKN1A. Western blotting was performed to determine protein levels of PNO1, p53, and p21. HCT-8 cells were transduced with a lentivirus over-expressing PNO1. Colony formation assay was used to detect cell survival in PNO1 overexpression of HCT-8 cells after PZH treatment. Cell-cycle distribution, cell viability and cell apoptosis were performed to identify the effect of PNO1 overexpression on cell proliferation and apoptosis of HCT-8 cells after PZH treatment. Xenograft BALB/c nude mice bearing HCT116 cells transduced with sh-PNO1 or sh-Ctrl lentivirus were evaluated. Western blot assay was performed to detect PNO1, p53, p21 and PCNA expression in tumor sections. Terminal deoxynucleotidyl transferase dUTP nick end labling (TUNEL) assay was used to determine the apoptotic cells in tissues.ResultsPZH treatment decreased cell viability, down-regulated PNO1 expression, and up-regulated p53 and p21 expressions in HCT-8 cells (P<0.05). PNO1 overexpression attenuated the effects of PZH treatment, including the expression of p53 and p21, cell growth, cell viability, cell cycle arrest and cell apoptosis in vitro (P<0.05). PNO1 knockdown eliminated the effects of PZH treatment on tumor growth, inhibiting cell proliferation inhibition and apoptosis induction in vivo (P<0.05). Similarly, PNO1 knockdown attenuated the effects of PZH treatment on the down-regulation of PNO1 and up-regulation of p53 and p21 in vivo (P<0.05).ConclusionThe mechanism by which PZH induces its CRC anti-proliferative effect is at least in part by regulating the expression of PNO1 and its downstream targets p53 and p21.

Oncogenic potential of IDH1R132C mutant incholangiocarcinoma development in mice

AIM: To investigate whether IDH1R132 C mutant in combination with loss of p53 and activated Notch signaling promotes intrahepatic cholangiocarcinoma(ICC) development.METHODS: We applied hydrodynamic injection and sleeping beauty mediated somatic integration to induce loss of p53(via sh P53), activation of Notch [via intracellular domain of Notch1(NICD)] and/or overexpression of IDH1R132 C mutant together with the sleeping beauty transposase into the mouse liver. Specifically, we co-expressed sh P53 and NICD(sh P53/NICD, n = 4), sh P53 and IDH1R132C(sh P53/IDH1R132 C, n = 3), NICD and IDH1R132C(NICD/IDH1R132 C, n = 4), as well as NICD, sh P53 and IDH1R132C(NICD/sh P53/IDH1R132 C, n = 9) in mice. Mice were monitored for liver tumor development and euthanized at various time points. Liver histology was analyzed by hematoxylin and eosin staining. Molecular features of NICD/sh P53/IDH1R132 C ICC tumor cells were characterized by Myc tag, Flag tag, Ki-67, p-Erk and p-AKT immunohistochemical staining. Desmoplastic reaction in tumor tissues was studied by Picro-Sirius red staining.RESULTS: We found that co-expression of sh P53/NICD, sh P53/IDH1R132 C or NICD/IDH1R132 C did not lead to liver tumor formation. In striking contrast, coexpression of NICD/sh P53/IDH1R132 C resulted in ICC development in mice(P < 0.01). The tumors could be identified as early as 12 wk post hydrodynamic injection. Tumors rapidly progressed, and by 18 wk post hydrodynamic injection, multiple cystic lesions could be identified on the liver surface. NICD/sh P53/IDH1R132 C liver tumors shared multiple histological features of human ICCs, including hyperplasia of irregular glands. Importantly, all tumor cells were positive for the biliary epithelial cell marker cytokeratin 19. Extensive collagen fibers could be visualized in tumor tissues using Sirus red staining, duplicating the desmoplastic reaction observed in human ICC. Tumors were highly proliferative and expressed ectopically injected genes. Together these studies supported that NICD/sh P53/IDH1R132 C liver tumors were indeed ICCs. Finally, no p-AKT or p-ERK positive staining was observed, suggesting that NICD/sh P53/IDH1R132 C driven ICC development was independent of AKT/m TOR and Ras/MAPK signaling cascades. CONCLUSION: We have generated a simple, nongermline murine ICC model with activated Notch, loss of p53 and IDH1R132 C mutant. The study supported the oncogenic potential of IDH1R132 C.

p53 promotes AKT and SP1-dependent metabolism through the pentose phosphate pathway that inhibits apoptosis in response to Nutlin-3a

Nutlin-3a is a MDM2 antagonist and preclinical drug that activates p53. Cells with MDM2 gene amplification are especially prone to Nutlin-3a-induced apoptosis, though the basis for this is unclear. Glucose metabolism can inhibit apoptosis in response to Nutlin-3a through mechanisms that are incompletely understood. Glucose metabolism through the pentose phosphate pathway （PPP） produces NADPH that can protect cells from potentially lethal reactive oxygen species （ROS）. We compared apoptosis and glucose metabolism in cancer cells with and without MDM2 gene amplification treated with Nutlin-3a. Apoptosis in MDM2-amplified cells was associated with a reduction in glycolysis and the PPP, reduced NADPH, increased ROS, and depletion of the transcription factor SP1, which normally promotes PPP gene expression. In contrast, glycolysis and the PPP were maintained or increased in MDM2 non-amplified cells treated with Nutlin-3a. This was dependent on p53-mediated AKT activation and was associated with maintenance of SP1 and continued expression of PPP genes. Knockdown or inhibition of AKT, SP1, or the PPP sensitized MDM2-non-amplified cells to apoptosis. The data indicate that p53 promotes AKT and SP1-dependent activation of the PPP that protects cells from Nutlin-3a-induced apoptosis. These findings provide insight into how glucose metabolism reduces Nutlin-3a-induced apoptosis, and also provide a mechanism for the heightened sensitivity of MDM2-amplified cells to apoptosis in response to Nutlin-3a.

Expressions of the Cell Cycle Relative Proteins in Esophageal Cancer Tissues

The aim of the research is to investigate the expression of the cell cycle relative proteins (P53, P16, Cyclin D1, and Ki67) in Esophageal Cancer (EC) patients of the Chaoshan area, China. In China, Chaoshan has the high incidence of EC. Different areas have shown different rate for expression of these proteins in EC. We investigated the expression of p53, p16, cyclinD1, and ki67 for the first time in Chaoshan. In this research, DNA was extracted from formalin fixed and paraffin embedded tissues of esophageal cancer (EC) patients. The expression level of proteins cycle was detected by using immunohistochemistry (IHC). And the data was checked by χ2 test or Fisher’s exact test of SPSS17.0. The positive immunohistochemical staining of p53, p16, cyclinD1, and ki67 were observed in 65.7% 39.2%, 69.1%, and 83.5% specimens respectively. There was a positive correlation between p53 positive staining and p16, cyclinD1, ki67 staining at p < 0.05. CyclinD1 has the high correlation with ki67 at p < 0.05. A significant inverse correlation was considered between the expression of p16 and cyclinD1 and there was no correlation observed between p16 and ki67. In Conclusion, this study demonstrated the high expression of p53, Cyclin D1 and Ki67 and low expression of P16 and the association of these cell cycle relative proteins in esophageal cancer are new data in Chaoshan area of China. Geographical distribution of EC on the molecular basis is revealed in this research.

Wip1 inhibits neutrophil extracellular traps to promote abscess formation in mice by directly dephosphorylating Coronin-1a

Neutrophil extracellular traps (NETs) participate in the rapid inhibition and clearance of pathogens during infection;however, the molecular regulation of NET formation remains poorly understood. In the current study, we found that inhibition of the wild-type p53-induced phosphatase 1 (Wip1) significantly suppressed the activity of Staphylococcus aureus (S. aureus) and accelerated abscess healing in S. aureus-induced abscess model mice by enhancing NET formation. A Wip1 inhibitor significantly enhanced NET formation in mouse and human neutrophils in vitro. High-resolution mass spectrometry and biochemical assays demonstrated that Coro1a is a substrate of Wip1. Further experiments also revealed that Wip1 preferentially and directly interacts with phosphorylated Coro1a than compared to unphosphorylated inactivated Coro1a. The phosphorylated Ser426 site of Coro1a and the 28–90 aa domain of Wip1 are essential for the direct interaction of Coro1a and Wip1 and for Wip1 dephosphorylation of p-Coro1a Ser426. Wip1 deletion or inhibition in neutrophils significantly upregulated the phosphorylation of Coro1a-Ser426, which activated phospholipase C and subsequently the calcium pathway, the latter of which promoted NET formation after infection or lipopolysaccharide stimulation. This study revealed Coro1a to be a novel substrate of Wip1 and showed that Wip1 is a negative regulator of NET formation during infection. These results support the potential application of Wip1 inhibitors to treat bacterial infections.

Mapping the Binding Site of P53 on UBC9 by NMR Spectroscopy

Human UBC9 is a member of the E2 family of proteins. However, instead of conjugating to ubiquitin, it conjugates to a ubiquitin homologue SUMO-1 (also known as UBL1, GMP1, SMTP3, PICT-1 and sentrin). The SUMO-1 conjugation pathway is very similar to that of ubiquitin with regard to the primary sequences of the ubiquitin activating enzymes (E1), the three-dimensional structures of the ubiquitin conjugating enzymes (E2), and the chemistry of the overall conjugation pathway. The interaction of p53 and UBC9, the E2 of the SUMO-1 pathway, has been studied by nuclear magnetic resonance spectroscopy. A peptide corresponding to the nuclear localization domain of p53 specifically interacts with UBC9 and this interaction is likely to be important for conjugation of p53 with SUMO-1. The largest chemical shift changes on UBC9 occur at residues 94 and 129-135. This region is adjacent to the active site and has significant dynamic behavior on the μs-ms and ps-ns timescales. Correlation of chemical shift changes and mobility of these residues further suggest the importance of these residues in substrate recognition.