p21Cip/WAF1 activation is an important factor for the ERK pathway dependent anti-proliferation of colorectal cancer cells

p21Cip/WAF1, an important regulator of cell proliferation, is induced by both p53- and extracellular signal regulated kinase (ERK) pathways. The induction of p21Cip/WAF1 occurs by prolonged activation of the ERKs caused by extracellular stimuli, such as zinc. However, not all the cells appeared to respond to ERK pathway dependent p21Cip/WAF1 induction. Here we investigated the cause of such difference using colorectal cancer cells. p21Cip/WAF1 induction and concomitant reduction of bromodeoxyuridine (BrdU) incorporation were observed by zinc treatment within HT-29 and DLD-1. However, HCT-116 cells with high endogenous p21Cip/WAF1 levels did not show any additional increment of p21Cip/WAF1 levels by zinc treatment and did maintain high BrdU incorporation level. The p21Cip/WAF1 induction by zinc depended upon prolonged activation of extracellular signal regulated kinase (ERK) was not observed in HCT-116 cells. The percentage of BrdU positive cells was 50% higher in p21Cip/WAF1 -/- HCT-116 cells compared to p21Cip/WAF1 +/+ HCT- 116 cells, and no cells induced p21Cip/WAF1 incorporated BrdU in its nucleus, yet confirming the importance of p21Cip/WAF1 induction in anti- proliferation. These results again support that p21Cip/WAF1 induction is a determinant in the regulation of colonic proliferation by the ERK pathway.     

Ionizing radiation induces blockade of c-Jun N-terminal kinase-dependent cell death pathway in a manner correlated with p21(Cip/WAF1) induction in primary cultured normal human fibroblasts

During radiotherapy of cancer, neighboring normal cells may receive sub-lethal doses of radiation. To investigate whether such low levels of radiation modulate normal cell responses to death stimuli, primary cultured human fibroblasts were exposed to various doses of gamma-rays. Analysis of cell viability using an exclusion dye propidium iodide revealed that the irradiation up to 10 Gy killed the fibroblasts only to a minimal extent. In contrast, the cells efficiently lost their viability when exposed to 0.5-0.65 mM H(2)O(2). This type of cell death was accompanied by JNK activation, and was reversed by the use of a JNK-specific inhibitor SP600125. Interestingly, H(2)O(2) failed to kill the fibroblasts when these cells were pre-irradiated, 24 h before H(2)O(2) treatment, with 0.25-0.5 Gy of gamma-rays. These cytoprotective doses of gamma-rays did not enhance cellular capacity to degrade H(2)O(2), but elevated cellular levels of p21(Cip/WAF1), a p53 target that can suppress H(2)O(2)-induced cell death by blocking JNK activation. Consistently, H(2)O(2)-induced JNK activation was dramatically suppressed in the pre-irradiated cells. The overall data suggests that ionizing radiation can impart normal fibroblasts with a survival advantage against oxidative stress by blocking the process leading to JNK activation.     

Trichostatin A-mediated upregulation of p21(WAF1) contributes to osteoclast apoptosis

Histone deacetylase inhibitors (HDIs), a new class of anti-cancer agents, have been reported to suppress formation of osteoclast precursors and their fusion into multinucleated cells. However, little is known about the effect of HDIs on mature osteoclasts, which may have significance for their therapeutic use. Here, we demonstrate a novel action of HDIs on osteoclast apoptosis. Primary multinucleated mature osteoclasts were prepared from mouse bone marrow cells. Treatment of osteoclasts with the HDI trichostatin A (TSA) caused apoptosis, as confirmed by annexin V staining and caspase activation. TSA caused the upregulation of p21WAF1 in osteoclasts. To understand the role of p21(WAF1) upregulation in TSA-treated osteoclasts, shRNA against p21(WAF1)-containing lentivirus was introduced into osteoclasts. The suppression of p21(WAF1) decreased TSA-directed osteoclast apoptosis. Collectively, our results provide evidence that TSA causes osteoclast apoptosis, which involves, in part, TSA-induced upregulation of p21(WAF1), and strongly supports HDIs as potential therapeutic agents for excessive bone resorption.     

Low-dose radiation response of the p21WAF1/CIP1 gene promoter transduced by adeno-associated virus vector

In cancer gene therapy, restriction of antitumor transgene expression in a radiation field by use of ionizing radiation-inducible promoters is one of the promising approaches for tumor-specific gene delivery. Although tumor suppressor protein p53 is induced by low doses (< 1 Gy) of radiation, there have been only a few reports indicating potential utilization of a p53-target gene promoter, such as that of the p21 gene. This is mainly because the transiently transfected promoter of p53-target genes is not much sensitive to radiation. We examined the response of the p21 gene promoter to low-dose radiation when transduced into a human breast cancer cell line MCF-7 by use of recombinant adeno-associated virus (rAAV) vectors. It was shown that the p21 gene promoter transduced by rAAV vectors was more highly radiation-responsive than that transiently transfected by electroporation. A significant induction of the p21 gene promoter by radiation of low doses down to 0.2 Gy was observed. When cells were transduced with the p21 gene promoter-driven HSVtk gene by rAAV vector, they were significantly sensitized to repetitive treatment with low dose radiation (1 Gy) in the presence of the prodrug ganciclovir. It was therefore considered that the p21 gene promoter in combination with a rAAV vector is potentially usable for the development of a low-dose radiation-inducible vector for cancer gene therapy.     

Visnagin inhibits cervical cancer cells proliferation through the induction of apoptosis and modulation of PI3K/AKT/mTOR and MAPK signaling pathway

Cervical cancer, a silent killer is a second most common type of malignant tumor detected in women’s world wide. In modern medicine the usage of phytochemicals to develop drugs for treating various chronic diseases is rapidly increasing. One such phytochemical is visnagin, a furanochrome present in fruits of Ammi visnaga. We investigated the anticarcinogenic potency of visnagin against human cervical carcinoma cells. The antioxidant potency of visnagin was analyzed with FRAP assay, DPPH assay, Chemiluminscence assay and ORAC assay. The cytotoxic effect of visnagin on normal epithelial Vero cells and human cervical cancer HeLa cells were analyzed using MTT assay. The effect of visnagin on antioxidant system was examined by measuring the levels of TBARS, SOD and GSH using the colorimetric assay techniques. DCFH-DA staining, AO/EtBr staining, propidium iodide staining was performed to assess the apoptotic induction potency of visnagin against cervical cancer cells. The ability of visnagin to inhibit cancer cell migration was examined with scratch wound assay. The anticarcinogenic property of visnagin was confirmed by analyzing the gene expression of PI3K/AKT/mTOR signaling proteins and MAPK signaling proteins using qPCR analysis. Visnagin exhibited increased Trolox equivalent value in all the four antioxidant potency estimating experiments. Visnagin induced cytotoxic effect only on carcinoma cells, decreased the antioxidants and increased the generation of ROS. It also induced apoptosis and inhibited the cancer cell migration. The qPCR analysis confirms visnagin decreases the gene expression cell cycle regulating protein of both PI3K/AKT/mTOR and MAPK pathway. Overall our results authentically prove visnagin inhibits the progression of cervical cancer in vitro. Therefore it can be an ideal drug of choice which can subject to further investigation for treating cervical cancer.     

Induction of G2/M Cell Cycle Arrest via p38/p21Waf1/Cip1-Dependent Signaling Pathway Activation by Bavachinin in Non-Small-Cell Lung Cancer Cells

Lung cancer is the most commonly diagnosed malignant cancer in the world. Non-small-cell lung cancer (NSCLC) is the major category of lung cancer. Although effective therapies have been administered, for improving the NSCLC patient’s survival, the incident rate is still high. Therefore, searching for a good strategy for preventing NSCLC is urgent. Traditional Chinese medicine (TCM) are brilliant materials for cancer chemoprevention, because of their high biological safety and low cost. Bavachinin, which is an active flavanone of Proralea corylifolia L., possesses anti-inflammation, anti-angiogenesis, and anti-cancer activities. The present study’s aim was to evaluate the anti-cancer activity of bavachinin on NSCLC, and its regulating molecular mechanisms. The results exhibited that a dose-dependent decrease in the cell viability and colony formation capacity of three NSCLC cell lines, by bavachinin, were through G2/M cell cycle arrest induction. Meanwhile, the expression of the G2/M cell cycle regulators, such as cyclin B, p-cdc2^Y15, p-cdc2^T161, and p-wee1, was suppressed. With the dramatic up-regulation of the cyclin-dependent kinase inhibitor, p21^Waf1/Cip1, the expression and association of p21^Waf1/Cip1 with the cyclin B/cdc2 complex was observed. Silencing the p21^Waf1/Cip1 expression significantly rescued bavachinin-induced G2/M cell accumulation. Furthermore, the expression of p21^Waf1/Cip1 mRNA was up-regulated in bavachinin-treated NSCLC cells. In addition, MAPK and AKT signaling were activated in bavachinin-added NSCLC cells. Interestingly, bavachinin-induced p21^Waf1/Cip1 expression was repressed after restraint p38 MAPK activation. The inhibition of p38 MAPK activation reversed bavachinin-induced p21^Waf1/Cip1 mRNA expression and G2/M cell cycle arrest. Collectively, bavachinin-induced G2/M cell cycle arrest was through the p38 MAPK-mediated p21^Waf1/Cip1-dependent signaling pathway in the NSCLC cells.     

Dexamethasone-induced differentiation of pancreatic AR42J cell involves p21(waf1/cip1) and MAP kinase pathway

Dexamethasone converts pluripotent pancreatic AR42J cells into exocrine cells expressing digestive enzymes. In order to address molecular mechanism of this differentiation, we have investigated the role of mitogen-activated protein (MAP) kinase pathway and gene expressions of p21(waf1/cip1) and nuclear oncogenes (c-fos and c-myc) during AR42J cell differentiation. Dexamethasone markedly increased the intracellular and secreted amylase contents as well as its mRNA level. However, cell growth and DNA content were significantly decreased. With these phenotypic changes, AR42J cells induced transient mRNA expression of p21(waf1/cip1) gene, which reached maximal level by 6 h and then declined gradually toward basal state. In contrast to p21(waf1/cip1), c-fos gene expression was transiently inhibited by 6 h and then recovered to basal level by 24 h. Increased c-myc expression detected after 3 h, peaked by 12 h, and remained elevated during the rest of observation. Dexamethasone inhibited epidermal growth factor-induced phosphorylation of extracellular signal regulated kinase. Inhibition of MAP kinase pathway by PD98059 resulted in further elevation of the dexamethasone-induced amylase mRNA and p21(waf1/cip1) gene expression. These results suggest that p21(waf1/cip1) and nuclear oncogenes are involved in dexamethasone-induced differentiation and inhibition of MAP kinase pathway accelerates the conversion of undifferentiated AR42J cells into amylase-secreting exocrine cells.     

Phosphoinositide-3-kinases (PI3Ks): combined comparative modeling and 3D-QSAR to rationalize the inhibition of p110alpha

The p110alpha isoform of the class IA PI3Ks was recently genetically validated as a promising target for anticancer therapy. However, up to now, only one compound (PIK75 = 1) has been reported as a very potent and selective inhibitor of this isoform. The lack of a 3D structure for this enzyme has clearly hindered the discovery of new p110alpha selective compounds. In view of this, we combined target-based (homology modeling) and ligand-based (3D-QSAR) approaches in an attempt to define an integrated interaction model for p110alpha inhibition. Twenty-five analogues of 1 were docked within the putative p110alpha binding site, and the molecular alignment generated was subsequently used to derive QSAR models based on scoring function, free energy of binding, CoMFA. and CoMSIA. The predictive power of these models was then analyzed using a challenging test set of 5 compounds. CoMSIA, and particularly CoMFA, models were found to outperform the other methods, predicting accurately the potency of 100% of the compounds in the test set, thereby validating our p110alpha homology model for use in further drug development.     

Collisional deactivation of Ba 5d7p (3)D1 by noble gases

Collisional deactivation of the 5d7p (3)D1 state of Ba by noble gases is studied by time- and wavelength-resolved fluorescence techniques. A pulsed, frequency-doubled dye laser at 273.9 nm excites the 5d7p (3)D1 level from the ground state, and fluorescence at 364.1 and 366.6 nm from the 5d7p (3)D1 --> 6s5d (3)D1 and 5d7p (3)D1 --> 6s5d (3)D2 transitions, respectively, is monitored in real time to obtain the deactivation rate constants. At 835 K these rate constants are as follows: He, (1.69 +/- 0.08) x 10(-9) cm(3) s(-1); Ne, (3.93 +/- 0.14) x 10(-10) cm(3) s(-1); Ar, (4.53 +/- 0.15) x 10(-10) cm(3) s(-1); Kr, (4.64 +/- 0.13) x 10(-10) cm(3) s(-1); Xe, (5.59 +/- 0.22) x 10(-10) cm(3) s(-1). From time-resolved 5d7p (3)D1 emission in the absence of noble gas and from the intercepts of the quenching plots, the lifetime of this state is determined to be 100 +/- 1 ns. Using time- and wavelength-resolved Ba emission with a low background pressure of noble gas, radiative lifetimes of several near-resonant states are determined from the exponential rise of the fluorescence signals. These results are as follows: 5d6d (3)D3, 28 +/- 3 ns; 5d7p (3)P1, 46 +/- 2 ns; 5d6d (3)G3, 21.5 +/- 0.8 ns; 5d7p (3)F3, 48 +/- 1 ns. Integrated fluorescence signals are used to infer the relative rate constants for population transfer from the 5d7p (3)D1 state to eleven near-resonant fine structure states.     

Regulation of the PI3K/AKT/mTOR signaling pathway with synthesized bismuth oxide nanoparticles from Ginger (Zingiber officinale) extract: Mitigating the proliferation of colorectal cancer cells

In order to overcome the limitations of conventional therapeutic systems in the treatment of cancer, nanoparticles (NPs) have been rapidly produced and developed as a separate treatment method for control of cancer. Synthesis of nanoparticles using plant-based materials (green synthesis), due to the easy and cost-effective synthesis, production of non-toxic, sustainable and environmentally friendly products, can be considered the most appropriate method for preparation of NPs. In this study, after synthesis of Bi₂O₃ NPs using Ginger (Zingiber officinale) root (rhizome) extract, the synthesized NPs were characterized and their potential application as selective anticancer agents against HCT116 colorectal cancer cells was evaluated through regulation of PI3K/AKT/mTOR signaling pathway, whereas the human kidney (HK-2) cells were used as normal cells. FTIR analysis showed a band at 673 cm^?1 attributed to Bi-O vibration with a fingerprint region at 1291 cm^?1 demonstrating the attachment of the organic molecules to the synthesized Bi₂O₃ NPs. UV–visible study showed a λ_max of around 268 nm, whereas XRD analysis showed eight clear peaks, demonetizing the crystalline phase of synthesized Bi₂O₃ NPs. TEM analysis showed that spherical-shaped Bi₂O₃ NPs have a size range of 20–50 nm with a man size of around 35 nm. Finally, DLS analysis determined that Bi₂O₃ NPs have a hydrodynamic size of about 71.19 nm (PDI of 0.179) and a zeta potential value of ?44.39 mV, revealing the good colloidal stability of NPs. Cellular assays (MTT, LDH, flow cytometry, and RT-qPCR) showed that synthesized Bi₂O₃ NPs selectively induced anticancer effects against HCT116 colorectal cancer cells through membrane leakage, generation of ROS, induction of apoptosis via dysregulation of Bax, Bcl-2 and caspase-3 at mRNA level mediated via regulation of PI3K/AKT/mTOR signaling pathway. In conclusion, it may be suggested that the presence study could provide useful information for the potential anticancer effects mediated by synthesized Bi₂O₃ NPs in vitro, although further studies, including in vivo studies and clinical trials, are needed to support our findings.     

A cyclometalated iridium(III) complex induces apoptosis and autophagy through inhibition of the PI3K/AKT/mTOR pathway

An iridium(III) complex [Ir(ppy)₂(MHPIP)]PF₆ (ppy = 2-phenylpyridine, MHPIP = 2-(1-methyl-1H-pyrazol-3-yl)-1H-imidazo[4,5-f][1, 10]phenanthroline, Ir-1) was synthesized and characterized by elemental analysis, IR, ¹H NMR and ¹³C NMR. The in vitro cytotoxic activities of the free proligand MHPIP and the complex Ir-1 against HepG2, A549, BEL-7402, SGC-7901 and normal LO2 cells were evaluated by the MTT method. MHPIP has no cytotoxic activity toward the selected cell lines, while Ir-1 shows a moderate cytotoxic effect against HepG2. This complex also displays no cytotoxicity against normal LO2 cells, with an IC₅₀ of more than 200 µM. The apoptosis of HepG2 cells induced by the complex was studied with AO/EB and DAPI staining methods, which showed that the complex can effectively induce apoptosis. A comet assay was performed by gel electrophoresis, and the results further show that the complex can cause apoptosis. The level of reactive oxygen species, mitochondrial membrane potential, autophagy, intracellular Ca²⁺ levels and cell invasion were investigated by fluorescence microscopy, and the cell cycle arrest was studied by flow cytometry. The expression of caspase and Bcl-2 family proteins was investigated by western blot. The results of these experiments indicate that Ir-1 accumulates preferentially in the mitochondria of HepG2 cells and induces apoptosis through inhibition of the PI3K/AKT/mTOR pathway.     

Mechanisms and Kinetics of Reactions of the O (1D,3p) + CF3Cl System

In the stratosphere, CF3Cl (CFC 13) can either photodecompose or react directly with atomic oxygen to generate ozone-depleting agents such as Cl and ClO in the gas phase[1-3]. Since the 1970s, attention has been focused on the effects of these compounds on the destruction of ozone in the stratosphere and on global warming[4,5].     

Lifetime measurements of the 3d 94s(1 D) 4p configuration of Cu I

The radiative lifetimes of the levels in the 3d ⁹4s(¹ D)4p configuration of Cu I are measured. The levels are excited from the metastable 3d ⁹4s ^{2 2} D _3/2,5/2 levels. The metastable Cu atoms are generated in a pulsed hollow cathode discharge. The levels investigated are populated with a 35-ps laser pulse at wavelengths around 220 nm. The laser induced fluorescence signal is detected. The lifetime of the 3d ⁹4s(³ D)4p ⁴ D _1/2 level is also determined by direct excitation from the ground state. A comparison with calculated literature values is given.     

Dynamics of the reactions of Mg(3s3p1p1) with H2, HD,and D2: Rotational quantum state distributions of MgH (MgD) products

The initial bimodal distributions of product MgH(ν = 0) rotational states in the reaction of Mg(¹P₁) with H₂ or HD are found to be identical. Similar results were found for MgD (ν = 0) produced from D₂ or HD. From these as well as other recent results, it is proposed that both the predominant “high-N” as well as the minor “low-N” components of the distributions result from insertion of Mg(¹P₁) into the H-H bond, and that there are two different primary modes of decomposition of the isotopic H-Mg-H intermediates.     

Lifetime measurements of the 2p 3d 3 D 1, 2, 3 0 and 2p 3d 1 P 1 0 levels in NII by beam-foil-laser spectroscopy

Accurate lifetimes measured by means of the cascade-free method based on laser excitation of a fast ion beam preexcited in a carbon foil are reported for four 2p 3d levels in NII. The lifetime results are: τ(2p 3d ³ D ₁ ⁰ )=0.209±0.007 ns, τ(2p 3d ³ D ₂ ⁰ )=0.219±0.007 ns, τ(2p 3d ³ D ₃ ⁰ )=0.217±0.005 ns, and τ(2p 3d ¹ P ₁ ⁰ )=0.410±0.017 ns. These results are compared to theoretical and experimental lifetimes reported previously.