Pharmocologic inhibitors of the mitogen activated protein kinase cascade have the potential to interact with ionizing radiation exposure to induce cell death in carcinoma cells by multiple mechanisms

Recent studies have shown that inhibition of stress-induced signaling via the mitogen activated protein kinase (MAPK) pathway can potentiate the toxic effects of chemotherapeutic drugs and ionizing radiation. Because of these observations, we have further investigated the impact upon growth and survival of mammary (MDA-MB-231, MCF7, T47D), prostate (DU145, LNCaP, PC3) and squamous (A431) carcinoma cells following irradiation and combined long-term exposure to MEK1/2 inhibitors. Exposure of carcinoma cells to ionizing radiation resulted in MAPK pathway activation initially (0-4h) and modestly enhanced MAPK activity at later times (24h-96h). Inhibition of radiation-induced MAPK activation using MEK1/2 inhibitors potentiated radiation-induced apoptosis in two waves, at 21-30h and 96-144h after exposure. The potentiation of apoptosis was not observed in MCF7, LNCaP, or PC3 cells. At 24h, the potentiation of apoptosis was independent of radiation dose whereas at 108h, apoptosis correlated with increasing dose. Removal of the MEK1/2 inhibitor either 6h or 12h after exposure abolished the potentiation of apoptosis at 24h. At this time, the potentiation of apoptosis correlated with cleavage of pro-caspases -8, -9 and -3, and with release of cytochrome c into the cytosol. Inhibition of caspase function using a pan-caspase inhibitor ZVAD blocked the enhanced apoptotic response at 24h. Selective inhibition of caspase 9 with LEHD or caspase 8 with IETD partially blunted the apoptotic response in MDA-MB-231, DU145 and A431 cells, whereas inhibition of both caspases reduced the response by >90%. Removal of the MEK1/2 inhibitor either 24h or 48h after exposure abolished the potentiation of apoptosis at 108h. Incubation of cells with ZVAD for 108h also abolished the potentiation of apoptosis. In general agreement with the finding that prolonged inhibition of MEK1/2 was required to enhance radiation-induced apoptosis at 108h, omission of MEK1/2 inhibitor from the culture media during assessment of clonogenic survival resulted in either little or no significant alteration in radiosensitivity. Collectively, our data show that combined exposure to radiation and MEK1/2 inhibitors can reduce survival in some, but not all, tumor cell types. Prolonged blunting of MAPK pathway function following radiation exposure is required for MEK1/2 inhibitors to have any effect on carcinoma cell radiosensitivity.Fil: Qiao, Liang. Virginia Commonwealth University; Estados UnidosFil: Yacoub, Adly. Virginia Commonwealth University; Estados UnidosFil: McKinstry, Robert. Virginia Commonwealth University; Estados UnidosFil: Park, Jong Sung. Virginia Commonwealth University; Estados UnidosFil: Caron, Ruben Walter. Virginia Commonwealth University; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Fisher, Paul B.. Columbia University. College of Physicians and Surgeons; Estados UnidosFil: Hagan, Michael P.. Virginia Commonwealth University; Estados UnidosFil: Grant, Steven. Virginia Commonwealth University; Estados UnidosFil: Dent, Paul. Virginia Commonwealth University; Estados Unido

Baryonic Response of Dense Holographic QCD

The response function of a homogeneous and dense hadronic system to a time-dependent (baryon) vector potential is discussed for holographic dense QCD (D4/D8 embedding) both in the confined and deconfined phases. Confined holographic QCD is an uncompressible and static baryonic insulator at large N_c and large \lambda, with a gapped vector spectrum and a massless pion. Deconfined holographic QCD is a diffusive conductor with restored chiral symmetry and a gapped transverse baryonic current. Similarly, dense D3/D7 is diffusive for any non-zero temperature at large N_c and large \lambda. At zero temperature dense D3/D7 exhibits a baryonic longitudinal visco-elastic mode with a first sound speed \lambda/\sqrt{3} and a small width due to a shear viscosity to baryon ratio \eta/n_B=\hbar/4. This mode is turned diffusive by arbitrarily small temperatures, a hallmark of holography.Comment: V2: 47 pages, 7 figures, references added, typos correcte

Primary versus radiation-associated craniofacial osteosarcoma

BACKGROUND. Craniofacial osteosarcoma differs from long bone osteosarcoma in that patients are older, tumors are often low grade, and prognosis is more favorable. Although most are sporadic, some tumors occur in association with prior radiation therapy. The purpose of the current study was to compare clinicopathologic and prognostic features of primary and radiation-associated osteosarcoma. METHODS. The study group consisted of 15 primary and 6 radiation-associated osteosarcomas. Clinical and follow-up data were obtained in every case. Tissue microarrays were immunohistochemically stained for p53, pRB, Ki-67 (MIB-1), and ezrin. DNA was sequenced for TP53 mutations. RESULTS. All radiation-associated osteosarcomas were high grade and half were fibroblastic. In contrast, 47% of primary craniofacial osteosarcomas were high grade and only 1 was fibroblastic. All radiation-associated osteosarcomas recurred, half the patients died of disease, 2 were alive with unresectable tumors, whereas only 1 was alive without disease. In contrast, 80% of patients with primary tumors were alive without disease, 33% had local recurrences, and 13% died of disease. Radiation-associated tumors overexpressed p53 more often (33% vs. 13%), more often had TP53 mutations (33% vs. 8%), had higher proliferative activity (67% vs. 0% showing >50% MIB-1 staining), and expressed ezrin more frequently (83% vs. 40%) than primary tumors. Compared with a control group of 24 high- and 7 low-grade primary extremity osteosarcomas, radiation-associated tumors marked as the high-grade tumors. CONCLUSIONS. Craniofacial radiation-associated osteosarcomas are high-grade tumors that behave more aggressively than most primary craniofacial osteosarcomas. In addition, they demonstrate higher expression rates of adverse prognostic indicators, further highlighting the distinction. Cancer 2006. © 2006 American Cancer Society.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/55776/1/22019_ftp.pd

Reaction profiling of a set of acrylamide-based human tissue transglutaminase inhibitors

The major function of the enzyme human tissue transglutaminase (TG2) is the crosslinking of proteins via a transamidation between the γ-carboxamide of a glutamine and the ε-amino group of a lysine. Overexpression of TG2 can lead to undesirable outcomes and has been linked to conditions such as fibrosis, celiac disease and neurodegenerative diseases. Accordingly, TG2 is a tempting drug target. The most effective TG2 inhibitors to date are small-molecule peptidomimetics featuring electrophilic warheads that irreversibly modify the active site catalytic cysteine (CYS277). In an effort to facilitate the design of such TG2 inhibitors, we undertook a quantum mechanical reaction profiling of the Michael reaction between a set of six acrylamide-based known TG2 inhibitors and the TG2 CYS277. The inhibitors were docked into the active site and the coordinates were refined by MD simulations prior to modelling the covalent modification of the CYS277 thiolate. The results of QM/MM MD umbrella sampling applied to reaction coordinates driving the Michael reaction are presented for two approximations of the Michael reaction: a concerted reaction (simultaneous thiolate attack onto the acrylamide warhead and pronation from the adjacent HIS335) and a two-stage reaction (consecutive thiolate attack and protonation). The two-stage approximation of the Michael reaction gave the better results for the evaluation of acrylamide-based potential TG2 inhibitors in silico. Good correlations were observed between the experimental TG2 IC50 data and the calculated activation energies over the range 0.0061 – 6.3 µM (three orders of magnitude) and we propose that this approach may be used to evaluate acrylamide-based potential TG2 inhibitors

Investigation of the Transient Behavior of a Cantilever Beam Using PVDF Sensors

In this paper, a PVDF film sensor was used to measure the transient responses of a cantilever beam subjected to an impact loading. The measurement capability of a PVDF sensor is affected by the area of the PVDF film sensor and the signal conditioner (charge amplifier). The influences of these effects on the experimental measurements were investigated. The transient responses for the dynamic strain of the beam were measured simultaneously by the PVDF sensor and a conventional strain gauge. The resonant frequencies of the beam were determined by applying the Fast Fourier Transform on transient results in the time domain of the PVDF sensor and the strain gauge. The experimentally measured resonant frequencies from the PVDF sensor and the strain gauge were compared with those predicted from theoretical and FEM numerical calculations. Based on the comparison of the results measured for these two sensors, the PVDF film sensor proved capable of measuring transient responses for dynamic strain, and its sensitivity is better than that of the strain gauge. Furthermore, almost all the resonant frequencies can be obtained from the results of transient responses for PVDF film

Immune-Related Gene Expression in Two B-Complex Disparate Genetically Inbred Fayoumi Chicken Lines Following Eimeria maxima Infection

To investigate the influence of genetic differences in the MHC on susceptibility to avian coccidiosis, M5.1 and M15.2 B-haplotype-disparate Fayoumi chickens were orally infected with live Eimeria maxima oocysts, and BW gain, fecal oocyst production, and expression of 14 immune-related genes were determined as parameters of protective immunity. Weight loss was reduced and fecal parasite numbers were lower in birds of the M5.1 line compared with M15.2 line birds. Intestinal intraepithelial lymphocytes from M5.1 chickens expressed greater levels of transcripts encoding interferon-γ (IFN-γ), interleukin-1β (IL-1β), IL-6, IL-8, IL-12, IL-15, IL-17A, inducible nitric oxide synthase, and lipopolysaccharide-induced tumor necrosis factor-α factor and lower levels of mRNA for IFN-α, IL-10, IL-17D, NK-lysin, and tumor necrosis factor superfamily 15 compared with the M15.2 line. In the spleen, E. maxima infection was associated with greater expression levels of IFN-γ, IL-15, and IL-8 and lower levels of IL-6, IL-17D, and IL-12 in M5.1 vs. M15.2 birds. These results suggest that genetic determinants within the chicken MHC influence resistance to E. maxima infection by controlling the local and systemic expression of immune-related cytokine and chemokine genes

Idiopathic Palmar Fasciitis with Polyarthritis Syndrome

A 31-yr-old Korean woman was presented with 4-month history of bilateral hand swelling and stiffness. On clinical examination, she had a painful synovitis of both hands, wrists, knees and ankles. The radiologic and histological examinations confirmed it with palmar fasciitis and polyarthritis syndrome (PFPAS). PFPAS is an uncommon disorder characterized by progressive flexion contractures of both hands, inflammatory fasciitiis, fibrosis, and a generalized inflammatory arthritis. Although most reported cases of PFPAS have been associated with various malignancies, our patient have not been associated with malignancy during 24 months follow up period from her first symptom onset. Her symptoms were improved with moderate dose of corticosteroid and she is currently taking prednisone 5 mg daily without any evidence for internal malignancy. We present here in a young Korean patient with idiopathic PFPAS who was successfully treated with administration of corticosteroid

Tumor Margin Histology Predicts Tumor Aggressiveness in Papillary Thyroid Carcinoma: A Study of 514 Consecutive Patients

Histologic patterns at tumor margins may be related to prognosis in several malignancies. We investigated tumor aggressiveness with respect to tumor margin histology in patients with papillary thyroid carcinoma (PTC). Five hundred fourteen consecutive patients who underwent surgery for primary PTC between January and July 2009 were assigned to two groups, one with an infiltrative pattern (I-type, n = 347) at tumor margins and one with an expanding pattern (E-type, n = 167). Tumor aggressiveness was assessed by analyzing relationships between these patterns and known prognostic factors. The analysis showed that unfavorable prognostic factors such as tumor multiplicity (P = 0.002), extrathyroidal extension (P < 0.001), lateral neck lymph node metastasis (P < 0.001) and advanced TNM stage (P = 0.001) were significantly more prevalent in patients with I-type PTC than in those with the E-type. Central neck node metastases were more prevalent without statistical significance in the I-type patients (P = 0.376). Tumor margin histology was not related to gender or tumor size. These results suggest that histologic patterns at tumor margins predict aggressiveness in PTC

Regulation of the catalytic function of topoisomerase II alpha through association with RNA

Topoisomerase IIα interacts with numerous nuclear factors, through which it is engaged in diverse nuclear events such as DNA replication, transcription and the formation or maintenance of heterochromatin. We previously reported that topoisomerase IIα interacts with RNA helicase A (RHA), consistent with a recent view that topoisomerases and helicases function together. Intrigued by our observation that the RHA–topoisomerase IIα interaction is sensitive to ribonuclease A, we explored whether the RHA–topoisomerase IIα interaction can be recapitulated in vitro using purified proteins and a synthetic RNA. This work led us to an unexpected finding that an RNA-binding activity is intrinsically associated with topoisomerase IIα. Topoisomerase IIα stably interacted with RNA harboring a 3′-hydroxyl group but not with RNA possessing a 3′-phosphate group. When measured in decatenation and relaxation assays, RNA binding influenced the catalytic function of topoisomerase IIα to regulate DNA topology. We discuss a possible interaction of topoisomerase IIα with the poly(A) tail and G/U-rich 3′-untranslated region (3′-UTR) of mRNA as a key step in transcription termination