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[Effect of microRNA-34a/SIRT1/p53 signal pathway on notoginsenoside R₁ delaying vascular endothelial cell senescence].
Lai, XH, Lei, Y, Yang, J, Xiu, CK
Zhongguo Zhong yao za zhi = Zhongguo zhongyao zazhi = China journal of Chinese materia medica. 2018;(3):577-584
Abstract
This study aimed to investigate the effect of notoginsenoside R₁ in delaying H₂O₂-induced vascular endothelial cell senescence through microRNA-34a/SIRT1/p53 signal pathway. In this study, human umbilical vein endothelial cells(HUVECs) were selected as the study object; the aging model induced by hydrogen peroxide(H₂O₂) was established, with resveratrol as the positive drug. HUVECs were randomly divided into four groups, youth group, senescence model group, notoginsenoside R₁ group and resveratrol group. Notoginsenoside R₁ group and resveratrol group were modeled with 100 μmoL·L⁻¹ H₂O₂ for 4 h after 24 h treatment with notoginsenoside R₁(30 μmoL·L⁻¹) and resveratrol(10 μmoL·L⁻¹) respectively. At the end, each group was cultured with complete medium for 24 h. The degree of cellular senescence was detected by senescence-associated β-galactosidase(SA-β-Gal) staining kit, the cell viability was detected by cell counting kit-8, the cell cycle distribution was analyzed by flow cytometry, and the cellular SOD activity was detected by WST-1 method in each group. The expressions of SIRT1, p53, p21 and p16 proteins in HUVECs were detected by Western blot. In addition, the mRNA expressions of miRNA-34a, SIRT1 and p53 in HUVECs were assayed by Real-time PCR. These results indicated that notoginsenoside R₁ significantly reduced the positive staining rate of senescent cells, enhanced the cell proliferation capacity and intracellular SOD activity, decreased the proportion of cells in G₀/G₁ phase, and increased the percentage of cells in S phase simultaneously compared with the senescence model group. Moreover, notoginsenoside R₁ decreased the mRNA expressions of miRNA-34a and p53 and the protein expression of p53, p21 and p16.At the same time, notoginsenoside R₁ increased the protein and mRNA expressions of SIRT1. The differences in these results between the senescence model group and the notoginsenoside R₁ group were statistically significant(P<0.05). However, there was not statistically significant difference in these results between the notoginsenoside R₁ group and the resveratrol group. In conclusion, the senescence of endothelial cells induced by H₂O₂ can be used as a model for studying aging. Notoginsenoside R₁ has an obvious anti-aging effect on vascular endothelial cells in this study. The possible mechanism is that notoginsenoside R₁ can delay the senescence process of vascular endothelial cells induced by H₂O₂ by regulating microRNA-34a/SIRT1/p53 signal pathway.
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Bisphenol A induces DSB-ATM-p53 signaling leading to cell cycle arrest, senescence, autophagy, stress response, and estrogen release in human fetal lung fibroblasts.
Mahemuti, L, Chen, Q, Coughlan, MC, Qiao, C, Chepelev, NL, Florian, M, Dong, D, Woodworth, RG, Yan, J, Cao, XL, et al
Archives of toxicology. 2018;(4):1453-1469
Abstract
Experimental and/or epidemiological studies suggest that prenatal exposure to bisphenol A (BPA) may delay fetal lung development and maturation and increase the susceptibility to childhood respiratory disease. However, the underlying mechanisms remain to be elucidated. In our previous study with cultured human fetal lung fibroblasts (HFLF), we demonstrated that 24-h exposure to 1 and 100 µM BPA increased GPR30 protein in the nuclear fraction. Exposure to 100 μM BPA had no effects on cell viability, but increased cytoplasmic expression of ERβ and release of GDF-15, as well as decreased release of IL-6, ET-1, and IP-10 through suppression of NFκB phosphorylation. By performing global gene expression and pathway analysis in this study, we identified molecular pathways, gene networks, and key molecules that were affected by 100, but not 0.01 and 1 µM BPA in HFLF. Using multiple genomic and proteomic tools, we confirmed these changes at both gene and protein levels. Our data suggest that 100 μM BPA increased CYP1B1 and HSD17B14 gene and protein expression and release of endogenous estradiol, which was associated with increased ROS production and DNA double-strand breaks, upregulation of genes and/or proteins in steroid synthesis and metabolism, and activation of Nrf2-regulated stress response pathways. In addition, BPA activated ATM-p53 signaling pathway, resulting in increased cell cycle arrest at G1 phase, senescence and autophagy, and decreased cell proliferation in HFLF. The results suggest that prenatal exposure to BPA at certain concentrations may affect fetal lung development and maturation, and thereby affecting susceptibility to childhood respiratory diseases.
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Downregulation of p53 drives autophagy during human trophoblast differentiation.
Gauster, M, Maninger, S, Siwetz, M, Deutsch, A, El-Heliebi, A, Kolb-Lenz, D, Hiden, U, Desoye, G, Herse, F, Prokesch, A
Cellular and molecular life sciences : CMLS. 2018;(10):1839-1855
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Abstract
The placental barrier is crucial for the supply of nutrients and oxygen to the developing fetus and is maintained by differentiation and fusion of mononucleated cytotrophoblasts into the syncytiotrophoblast, a process only partially understood. Here transcriptome and pathway analyses during differentiation and fusion of cultured trophoblasts yielded p53 signaling as negative upstream regulator and indicated an upregulation of autophagy-related genes. We further showed p53 mRNA and protein levels decreased during trophoblast differentiation. Reciprocally, autophagic flux increased and cytoplasmic LC3B-GFP puncta became more abundant, indicating enhanced autophagic activity. In line, in human first trimester placenta p53 protein mainly localized to the cytotrophoblast, while autophagy marker LC3B as well as late autophagic compartments were predominantly detectable in the syncytiotrophoblast. Importantly, ectopic overexpression of p53 reduced levels of LC3B-II, supporting a negative regulatory role on autophagy in differentiating trophoblasts. This was also shown in primary trophoblasts and human first trimester placental explants, where pharmacological stabilization of p53 decreased LC3B-II levels. In summary our data suggest that differentiation-dependent downregulation of p53 is a prerequisite for activating autophagy in the syncytiotrophoblast.
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Pyran-2-one derivatives from Croton crassifolius as potent apoptosis inducers in HepG2 cells via p53-mediated Ras/Raf/ERK pathway.
Tian, JL, Yao, GD, Zhang, YY, Lin, B, Zhang, Y, Li, LZ, Huang, XX, Song, SJ
Bioorganic chemistry. 2018;:355-362
Abstract
Chemical investigation of the roots of Croton crassifolius led to the isolation of five pyran-2-one derivatives, including two brand new compounds (1-2), one new natural product (3) and two known compounds (4-5). Their structures and absolute configurations were established by spectroscopic analyses as well as comparison between the calculated optical rotation (OR) values with the experimental data. Interestingly, the new compound 1 showed an unusual negative chemical shift at H-11. It is well known that negative chemical shift values of 1H NMR spectrum are extremely rare in natural products. Such a negative chemical shift of 1H NMR spectrum was reproduced by density functional theory (DFT) calculations and explained by the shielding effect from the pyran-2-one ring over the hydrogen atom in the 3D conformations. Then, MTT assay was applied to evaluate the cytotoxicity of the isolated compounds (1-5) against two liver cancer cell lines (HepG2 and MHCC97H). The results suggested that compound 1 displayed the highest cytotoxicity with an IC50 value of 9.8 μM against HepG2 cells. Moreover, there was no obvious cytotoxicity of compounds 1-5 on normal liver cell line LO2. Furthermore, the mechanism of apoptosis induction in compound 1-treated HepG2 cells was investigated. The results showed that compound 1 could induce apoptosis via p53-mediated Ras/Raf/ERK suppression in HepG2 cells.
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Advances in sarcoma gene mutations and therapeutic targets.
Gao, P, Seebacher, NA, Hornicek, F, Guo, Z, Duan, Z
Cancer treatment reviews. 2018;:98-109
Abstract
Sarcomas are rare and complex malignancies that have been associated with a poor prognostic outcome. Over the last few decades, traditional treatment with surgery and/or chemotherapy has not significantly improved outcomes for most types of sarcomas. In recent years, there have been significant advances in the understanding of specific gene mutations that are important in driving the pathogenesis and progression of sarcomas. Identification of these new gene mutations, using next-generation sequencing and advanced molecular techniques, has revealed a range of potential therapeutic targets. This, in turn, may lead to the development of novel agents targeted to different sarcoma subtypes. In this review, we highlight the advances made in identifying sarcoma gene mutations, including those of p53, RB, PI3K and IDH genes, as well as novel therapeutic strategies aimed at utilizing these mutant genes. In addition, we discuss a number of preclinical studies and ongoing early clinical trials in sarcoma targeting therapies, as well as gene editing technology, which may provide a better choice for sarcoma patient management.
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Phase II Studies with Refametinib or Refametinib plus Sorafenib in Patients with RAS-Mutated Hepatocellular Carcinoma.
Lim, HY, Merle, P, Weiss, KH, Yau, T, Ross, P, Mazzaferro, V, Blanc, JF, Ma, YT, Yen, CJ, Kocsis, J, et al
Clinical cancer research : an official journal of the American Association for Cancer Research. 2018;(19):4650-4661
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Abstract
Purpose: Refametinib, an oral MEK inhibitor, has demonstrated antitumor activity in combination with sorafenib in patients with RAS-mutated hepatocellular carcinoma (HCC). Two phase II studies evaluated the efficacy of refametinib monotherapy and refametinib plus sorafenib in patients with RAS-mutant unresectable or metastatic HCC.Patients and Methods: Eligible patients with RAS mutations of cell-free circulating tumor DNA (ctDNA) determined by beads, emulsion, amplification, and magnetics technology received twice-daily refametinib 50 mg ± sorafenib 400 mg. Potential biomarkers were assessed in ctDNA via next-generation sequencing (NGS).Results: Of 1,318 patients screened, 59 (4.4%) had a RAS mutation, of whom 16 received refametinib and 16 received refametinib plus sorafenib. With refametinib monotherapy, the objective response rate (ORR) was 0%, the disease control rate (DCR) was 56.3%, overall survival (OS) was 5.8 months, and progression-free survival (PFS) was 1.9 months. With refametinib plus sorafenib, the ORR was 6.3%, the DCR was 43.8%, OS was 12.7 months, and PFS was 1.5 months. In both studies, time to progression was 2.8 months. Treatment-emergent toxicities included fatigue, hypertension, and acneiform rash. Twenty-seven patients had ctDNA samples available for NGS. The most frequently detected mutations were in TERT (63.0%), TP53 (48.1%), and β-catenin (CTNNB1; 37.0%).Conclusions: Prospective testing for RAS family mutations using ctDNA was a feasible, noninvasive approach for large-scale mutational testing in patients with HCC. A median OS of 12.7 months with refametinib plus sorafenib in this small population of RAS-mutant patients may indicate a synergistic effect between sorafenib and refametinib-this preliminary finding should be further explored. Clin Cancer Res; 24(19); 4650-61. ©2018 AACR.
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TP53 p.Arg337His germline mutation prevalence in Southern Brazil: Further evidence for mutation testing in young breast cancer patients.
Hahn, EC, Bittar, CM, Vianna, FSL, Netto, CBO, Biazús, JV, Cericatto, R, Cavalheiro, JA, de Melo, MP, Menke, CH, Rabin, E, et al
PloS one. 2018;(12):e0209934
Abstract
Premenopausal breast cancer (BC) is a core tumor of Li-Fraumeni (LFS) and Li-Fraumeni-like (LFL) Syndromes, predisposition disorders caused by germline mutations in TP53 gene. In the Southern and Southeastern regions of Brazil, a specific TP53 germline mutation, c.1010G>A (p.Arg337His), was identified at a population frequency of 0.3%, the highest value ever described for a TP53 germline variation. In Brazilian BC patients, carrier frequency can vary from 0.5% to 8.7%. The current study assessed carrier frequency by genotyping TP53 c.1010G>A in 2 BC groups: 1) 315 patients unselected for age of diagnosis and family history (FH) and 2) 239 patients diagnosed before 46 years and without Chompret criteria for LFS or LFL. One carrier was identified in group 1 (0.3%; CI 95% 0.1-1.76%) and six carriers in group 2 (2.5%; CI 95% 0.93-5.39%). The frequencies differed significantly between groups (p = 0.04). The mutation carrier frequency observed in group 2 could justify mutation testing in BC patients diagnosed before 46 years and without Chompret criteria for LFS or LFL. Further studies in larger samples of BC patients of different ages and regions of the country are necessary to provide more definitive TP53 p.Arg337His carrier frequencies in different scenarios.
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Apigenin, by activating p53 and inhibiting STAT3, modulates the balance between pro-apoptotic and pro-survival pathways to induce PEL cell death.
Granato, M, Gilardini Montani, MS, Santarelli, R, D'Orazi, G, Faggioni, A, Cirone, M
Journal of experimental & clinical cancer research : CR. 2017;(1):167
Abstract
BACKGROUND Apigenin is a flavonoid widely distributed in plant kingdom that exerts cytotoxic effects against a variety of solid and haematological cancers. In this study, we investigated the effect of apigenin against primary effusion lymphoma (PEL), a KSHV-associated B cell lymphoma characterized by a very aggressive behavior, displaying constitutive activation of STAT3 as well as of other oncogenic pathways and harboring wtp53. METHODS Cell death was assessed by trypan blue exclusion assay, FACS analysis as well as by biochemical studies. The latter were also utilized to detect the occurrence of autophagy and the molecular mechanisms leading to the activation of both processes by apigenin. FACS analysis was used to measure the intracellular ROS utilizing DCFDA. RESULTS We show that apigenin induced PEL cell death and autophagy along with reduction of intracellular ROS. Mechanistically, apigenin activated p53 that induced catalase, a ROS scavenger enzyme, and inhibited STAT3, the most important pro-survival pathway in PEL, as assessed by p53 silencing. On the other hand, STAT3 inhibition by apigenin resulted in p53 activation, since STAT3 negatively influences p53 activity, highlighting a regulatory loop between these two pathways that modulates PEL cell death/survival. CONCLUSION The findings of this study demonstrate that apigenin may modulate pro-apoptotic and pro-survival pathways representing a valid therapeutic strategy against PEL.
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Epoxy clerodane diterpene inhibits MCF-7 human breast cancer cell growth by regulating the expression of the functional apoptotic genes Cdkn2A, Rb1, mdm2 and p53.
Subash-Babu, P, Alshammari, GM, Ignacimuthu, S, Alshatwi, AA
Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie. 2017;:388-396
Abstract
Systematic analyses of plants that are used in traditional medicine may lead to the discovery of novel cytotoxic secondary metabolites. Diterpene possesses multiple bioactivities; here, epoxy clerodane diterpene (ECD) was isolated from Tinospora cordifolia (Willd.) stem and shown potential antiproliferative effect in MCF-7 human breast cancer cells. The antiproliferative effect of ECD on MCF-7 cells was systematically analyzed by cell and nuclear morphology, alterations in oxidative stress, and the expression of tumor suppressor and mitochondria-mediated apoptosis-related genes. We found that the IC50 value of ECD was 3.2μM at 24h and 2.4μM at 48h. We observed that the cytotoxicity of ECD was specific to MCF-7 cells, whereas ECD was nontoxic to normal Vero and V79 cells. ECD significantly triggered intracellular ROS generation even from the lower doses of 0.6 and 1.2μM; and it is relative to higher dose of 2.4μM. Further, we used 0.6μM, 1.2μM and 2.4μM as experimental doses to analyze the relative dose-dependent effects. Nuclear staining revealed that cells treated with the 2.4μM dose exhibited characteristic apoptotic morphological changes and that 46% of the cells were apoptotic and 4% were necrotic after 48h. ECD significantly increased the expression of mitochondria-dependent apoptotic pathway-related genes after 48h; we observed significantly (p≤0.05) increased expression of CYP1A, GPX, GSK3β and TNF-α and downregulated expression of NF-κB. ECD also increased the expression of tumor suppressor genes such as Cdkn2A, Rb1 and p53. In addition, we observed that ECD treatment significantly (p≤0.001) upregulated the expression of apoptotic genes such as Bax, cas-3, cas-8, cas-9 and p21 and downregulated the expression of BCL-2, mdm2 and PCNA. In conclusion, ECD regulates the expression of Cdkn2A, p53 and mdm2 and induces apoptosis via the mitochondrial pathway in MCF-7 human breast cancer cells.
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TLR9 stimulation of B-cells induces transcription of p53 and prevents spontaneous and irradiation-induced cell death independent of DNA damage responses. Implications for Common variable immunodeficiency.
Holm, KL, Syljuåsen, RG, Hasvold, G, Alsøe, L, Nilsen, H, Ivanauskiene, K, Collas, P, Shaposhnikov, S, Collins, A, Indrevær, RL, et al
PloS one. 2017;(10):e0185708
Abstract
In the present study, we address the important issue of whether B-cells protected from irradiation-induced cell death, may survive with elevated levels of DNA damage. If so, such cells would be at higher risk of gaining mutations and undergoing malignant transformation. We show that stimulation of B-cells with the TLR9 ligands CpG-oligodeoxynucleotides (CpG-ODN) prevents spontaneous and irradiation-induced death of normal peripheral blood B-cells, and of B-cells from patients diagnosed with Common variable immunodeficiency (CVID). The TLR9-mediated survival is enhanced by the vitamin A metabolite retinoic acid (RA). Importantly, neither stimulation of B-cells via TLR9 alone or with RA increases irradiation-induced DNA strand breaks and DNA damage responses such as activation of ATM and DNA-PKcs. We prove that elevated levels of γH2AX imposed by irradiation of stimulated B-cells is not due to induction of DNA double strand breaks, but merely reflects increased levels of total H2AX upon stimulation. Interestingly however, we unexpectedly find that TLR9 stimulation of B-cells induces low amounts of inactive p53, explained by transcriptional induction of TP53. Taken together, we show that enhanced survival of irradiated B-cells is not accompanied by elevated levels of DNA damage. Our results imply that TLR9-mediated activation of B-cells not only promotes cell survival, but may via p53 provide cells with a barrier against harmful consequences of enhanced activation and proliferation. As CVID-derived B-cells are more radiosensitive and prone to undergo apoptosis than normal B-cells, our data support treatment of CVID patients with CpG-ODN and RA.