Protein Levels Of PARP Research Articles

Altered oxidative DNA damage repair systems in muscles of old mice: role in the age‐related increase in muscle production of cytokines/chemokines

An increased presence of the oxidised DNA base lesion 8‐oxo‐7,8‐dihydroguanine (8‐oxoG) is seen in muscles of old mice. 8‐oxoG is repaired by the 8‐oxoguanine DNA glycosylase‐1 (OGG1)‐initiated DNA base excision repair pathway, a process proposed to lead to activation of nuclear factor kappa‐light‐chain‐enhancer of activated B cells (NF‐kB). We hypothesised that chronic oxidative DNA damage in muscles of old mice leads to the chronic increase in activation of NF‐kB by OGG1 and the subsequent production of inflammatory cytokines by skeletal muscle, contributing to age‐related deterioration of muscle function.An in vitro model of oxidative DNA damage was established by treating C2C12 myoblasts with H2O2. DNA damage repair responses including 8‐oxoG, OGG1, PARP‐1, NF‐kB activation and cytokine/chemokine gene expression and release by muscle cells were determined using Luminex multiplex analysis. The effect of TH5487 (5µM), a selective OGG1 inhibitor on NF‐kB activation and cytokine/chemokine production was determined. The role of OGG1 in the chronic production of cytokines/chemokines by isolated muscle fibres of adult mice treated with H2O2 and of old mice was examined. Cell viability was maintained in myoblasts treated with 50µM H2O2 but Ogg1 mRNA levels were significantly increased as was acetylation of OGG1, PARP‐1 and cleaved PARP‐1 protein levels. Activation of NF‐κB was evident and accompanied by an increased expression and release of a number of cytokines/chemokines (3.7 fold, 4.2 fold, 3 fold increases in IL‐6 TNF‐a and CXCL1 mRNA respectively). The H2O2‐mediated increase in NF‐kB activation and increase in cytokine/chemokine mRNA levels were normalized when cells were pre‐treated with TH5487 prior to treatment with H2O2. Experiments using isolated muscle fibers from adult mice demonstrated an increase in NF‐κB activation following treatment with H2O2. This H2O2‐mediated increase in NF‐kB DNA binding activity was significantly decreased in muscle fibers pre‐treated with TH5487. Isolated muscle fibers from old compared with adult mice showed an increase in cytokine/chemokine release which was also reduced by treatment with TH5487. Increases in IL‐6, CCL2,CXCL1,CCL7,CCL27,CXCL5,CCL11,CXCL16 and CXCL‐12 were seen in the media of fibers from adult mice following treatment with H2O2 and most of these were then decreased to normal values by pre‐treatment with TH5487. Isolated muscle fibers from old mice showed a significant increase in IL‐6, CXCL1,CCL2,CCL7, of which all were reduced following treatment with TH5487, suggesting that activation of the OGG1 pathway may be responsible, at least in part for the increased production of cytokines/chemokines by muscle of old mice. Data on proteomic and mRNA analyses of muscles from adult and old mice for evidence of changes in DNA repair pathways with age will also be presented. A computationalmodel of DNA damage repair is being designed to identify DNA damage repair process therapeutic targets to modify activation of NF‐κB in muscles of old mice.

PARP1, BRCA1 and androgen receptor expression in triple-negative breast cancer patients treated with neoadjuvant chemotherapy

IntroductionTriple-negative breast cancer (TNBC) is an aggressive subtype, where no effective therapies have been established for it. Searching for therapeutic targets for TNBC patients is the aim of the current research. Poly adenosine diphosphate ribose polymerase (PARP1) inhibitors are promising antitumor therapy that have a high potency in BRCA1-deficient breast cancers. Materials and methodsForty TNBC patients who received neoadjuvant chemotherapy (NAC) were enrolled in this study, and evaluated for PARP1, BRCA1, and Androgen receptor (AR) immunohistochemical expression before and after receiving NAC. Data of patients' clinical and pathological responses to the chemotherapy were collected and finally analyzed. ResultsThe immunohistochemical results revealed 10 cases (25%) positive for AR, while 18 cases (45%) and 22 cases (55%) expressed PARP1 at low and high levels, respectively. Twelve cases (30%) and 28 cases (70%) expressed BRCA1 at low and high levels, respectively. There was a significant difference between PARP1 expression in normal and malignant tissues (P < 0.001). Higher PARP1 expression was correlated with a better overall clinical response (OAR) and pathological complete response (pCR) (P = 0.018, 0.01 respectively). Co-expression of both PARP1 & BRCA1 was correlated with OAR and pCR. Chemotherapy decreases PARP1 protein levels in matched patient samples (P = 0.015). Positive AR expression was correlated with BRCA1 overexpression. ConclusionPARP1 is highly expressed in TNBC with a better OAR and pCR especially in cases with high BRCA1, so it might be considered as a therapeutic target for this risky group.

Novel piperazine-substituted silicon phthalocyanines exert anti-cancer effects against breast cancer cells

BackgroundPhotodynamic therapy (PDT) is one of the effective methods that can be used in cancer treatment. In this study, we aimed to investigate the PDT-mediated anti-cancer effects of newly synthesized piperazine-substituted silicon phthalocyanine molecules on breast cancer cells. MethodsThe compounds were analyzed by different spectroscopic techniques (FT-IR, UV–vis, 1H NMR, 13C NMR, MS) and the absorbance characteristics were determined. The cytotoxic effects of silicon phthalocyanines on MDA-MB-231 breast cancer cells and non-tumorigenic MCF-10A cells were evaluated using MTT assay. Detection of apoptotic populations was performed by Annexin V/7AAD assay. H2DCFDA dye was used to analyze intracellular reactive oxygen species. The clonogenic activity and cellular motility were analyzed by colony formation assay and in vitro scratch assay, respectively. Caspase-3, PARP1, and cleaved-PARP1 protein levels were analyzed by western blot studies. ResultsPiperazine-substituted silicon phthalocyanines caused high levels of cytotoxic effects and apoptotic cell population in MDA-MB-231 cells, while low levels of cytotoxic effects were observed in MCF-10A cells. Following PDT, intense ROS formation was detected in MDA-MB-231 cells. Colony-forming capacity and cellular motility of MDA-MB-231 cells were highly restricted following PDT, whereas these effects were observed at lower levels in MCF-10A cells. Silicon phthalocyanines caused different effects on cleaved-PARP1 expressions of MDA-MB-231 and MCF-10A cells. ConclusionThese results suggest that piperazine-substituted silicon phthalocyanines can exert selective anti-cancer effects on breast cancer cells and activate cellular death through different molecular pathways. Hence, we believe that they may be used as effective photosensitizer agents in the future.

Brassica juncea polysaccharides induce apoptosis of colorectal cancer cells via mitochondrial- and caspasedependent apoptosis pathways

Purpose: To determine the effect of polysaccharides from Gleditsia on apoptosis of colorectal cancer cells, and the mechanism involved.Methods: Polysaccharides were extracted from Lycium barbarum, and their concentration was more than 85 %. Then, DLD-1 cells were cultured in medium with the polysaccharides at concentrations of 75 and 150 μg/mL. Cell proliferation was determined with MTT (3-(4,5)-dimethylthiahiazo (-z-y1)-3,5- diphenytetrazoliumromide) assay and colony formation assay, while apoptosis was determined with flow cytometry. Changes in MMP were measured flow cytometrically. The protein levels of PARP, Bcl-2, Bax, and caspases 3 and 9 were determined with Western blot assay.Results: Cell viability decreased time-dependently. Compared with control without polysaccharide exposure, cell viability, colony forming cells, % apoptosis, red: green fluorescence ratio, and bcl-2 expression were significantly and concentration-dependently decreased, while the expression levels of PARP, Bax, caspase-3 and caspase-8 were significantly increased (p &lt; 0.05).Conclusion: These results indicate that the polysaccharides suppressed apoptosis of colorectal cancer cells by inhibiting the mitochondrial and caspase-dependent apoptosis pathways. Gleditsia polysaccharide may be used as an adjuvant therapy for colorectal cancer.

Pyrroline-5-Carboxylate Reductase-2 Promotes Colorectal Cancer Progression via Activating PI3K/AKT/mTOR Pathway.

Aim The aim of this study was to investigate the effect and underlying pathway of pyrroline-5-carboxylate reductase-2 (PYCR2) on colorectal cancer (CRC). Methods The Cancer Genome Atlas (TCGA) database was used to analyze PYCR2 expression levels and clinical information. Cell proliferation was evaluated using colony forming and EdU assay. Cell apoptosis rate was determined using flow cytometry. Cell migration and invasion were measured by performing a Transwell assay, and PYCR2, MMP-2, MMP-9, Bax, cleaved caspase-3, Bcl-2, cleaved PARP, p-PI3K, PI3K, p-AKT, AKT, p-mTOR, and mTOR protein levels were detected by Western blot. Results A review of the TCGA database revealed that PYCR2 was highly expressed in CRC patients and that high PYCR2 expression was associated with advanced stage, adenocarcinoma, nodal metastasis, and poor survival rate. Moreover, PYCR2 knockdown reduced cell viability, proliferation, migration, and invasion and increased apoptosis. Additionally, PYCR2 knockdown increased Bax, cleaved caspase-3, and cleaved PARP levels and decreased Bcl-2, MMP-2, MMP-9, p-PI3K, p-AKT, and p-mTOR levels in CRC cells. Effects of silencing PYCR2 on proliferation, migration, invasion, apoptosis, and the PI3K/AKT/mTOR pathway in CRC cells were all reversed using a PI3K activator (740Y-P). Conclusion PYCR2 was highly expressed in CRC, and its knockdown suppressed CRC tumorigenesis via inhibiting the activation of PI3K/AKT/mTOR pathway. This finding provides a new theoretical foundation for the treatment of CRC.

Ameliorating effects of white mulberry on iron-overload-induced oxidative stress and liver fibrosis in Swiss albino mice

Excess iron causes oxidative damage of biomolecules, leading to tissue injury primarily liver failure. In this study, we explored the remediating effects of Morus alba L. (MAME) on iron-overload-induced oxidative stress and liver injury in mice. The In vitro study revealed the antioxidant and free radical scavenging properties of MAME. Intraperitoneal injection of iron-dextran was administered in Swiss albino mice to induce iron-overload condition and the mice were further treated with MAME. MAME treatment significantly decreased liver iron, serum ferritin level, oxidative stress, and restored serum parameters and liver antioxidants. Moreover, biochemical and histopathological analyses confirmed the alleviated liver damage and fibrosis upon MAME treatment. The protective effect of MAME against iron-overload-induced apoptosis was confirmed by upregulation of protein levels of Bax, Caspase-3, and PARP. The treatment also affected the expression of MAPKs (ERK, JNK, and p38). GC-MS analysis revealed the presence of various bioactive phytochemicals in MAME that may be responsible for ameliorating effects of excess iron. Thus MAME can be envisaged as an effective iron chelator in the treatment of iron-overload-induced liver injury and fibrosis.

Retinoic acid exerts neuroprotective effects against focal cerebral ischemia by preventing apoptotic cell death

Cerebral ischemia is a neurological disorder that leads to cognitive decline and high mortality. Retinoic acid is a metabolite of vitamin A that has anti-inflammatory and anti-apoptotic effects. This study investigated whether retinoic acid prevents neuronal cell damage on focal cerebral ischemia through modulating apoptosis signaling pathway. Middle cerebral artery occlusion (MCAO) was performed to induce focal cerebral ischemia in adult male rats. Retinoic acid (5 mg/kg) or vehicle was injected intraperitoneally for 4 days prior to MCAO. Neurological behavior deficit tests were performed 24 h after MCAO. Brain edema and infarct volume were measured, and TUNEL histochemistry was carried out. We also investigated the changes in apoptosis-related proteins including bcl-2 family proteins and caspases. MCAO injury induced severe neurological behavior deficits and brain edema. It also increased infarct volume, histopathological damages, and the number of TUNEL-positive cells in cerebral cortex. However, retinoic acid pretreatment attenuated MCAO-induced neurological behavior deficits, brain edema, and infarction. It also alleviated histopathological lesion and decreased the number of TUNEL-positive cells. Bcl-2 and bax proteins are representative bcl-2 family proteins. MCAO injury induced a decrease in bcl-2 expression and an increase in bax expression, and retinoic acid pretreatment alleviated these changes. MCAO injury caused a decrease in bcl-2/bax expression ratio in cerebral cortex, while retinoic acid restored this decrease by MCAO. Moreover, our result showed increases in caspase-9, caspase-3, PARP protein levels in MCAO-operated animals. Retinoic acid pretreatment prevented these increases. We identified the changes in cleaved forms of these proteins, similar to the changes in full-length protein. Activation of caspases and PARP proteins are considered to be representative apoptosis indicators. This study showed that retinoic acid regulates bcl-2 family proteins and caspase proteins in focal cerebral ischemia. Thus, our findings demonstrate that retinoic acid exhibits a neuroprotective effect against ischemic damage by modulating apoptosis signaling pathway.

MiR-34a/SIRT1 Axis Modulating Therapeutic Effect of Olaparib on Pancreatic Cancer through Suppressing PARP1 and EMT

ABSTRACT This study analyzed functions of miR-34a and SIRT1 in modulating efficacy of Olaparib in pancreatic cancer in vitro. RNA expressions of miR-34a and SIRT1 were evaluated through RT-qPCR in HPDE6-C7, SW1990, PANC-1 and MIA PaCa-2 cells. MiR-34a was promoted in cancer cell lines while SIRT1 was decreased. Luciferase reporter assay verified bindings between miR-34a and SIRT1. Moreover, E-cadherin was promoted by miR-34a mimics and SIRT1 suppression while N-cadherin and Vimentin were both downregulated. Additionally, PARP1 protein expression was increased after miR- 34a promotion and SIRT1 downregulation. Besides that, PARP1 protein levels and EMT were significantly inhibited after treated by Olaparib (0, 0.5, 1 and 1.5ìM). In Olaparib-treated cancer cells, SIRT1, PARP1 and EMT were all distinctly decreased after SIRT1 suppression and overexpression of miR-34a induced much lower level of SIRT1.

Garcinielliptone G from Garcinia subelliptica Induces Apoptosis in Acute Leukemia Cells.

Cytotoxicity and apoptosis-inducing properties of compounds isolated from Garcinia subelliptica leaves were investigated. The hexane-soluble portion of MeOH extracts of G. subelliptica leaves that showed cytotoxic activity was separated to yield seven compounds 1–7. Chemical structure analysis using NMR spectroscopy and mass spectrometry confirmed that compound 1 was canophyllol, and compounds 2–7 were garcinielliptones N, O, J, G, F, and garcinielliptin oxide, respectively. Among them, garcinielliptone G (5) showed growth inhibition by causing apoptosis in THP-1 and Jurkat cells derived from human acute monocytic leukemia and T lymphocyte cells, respectively. Apoptosis induced by garcinielliptone G (5) was demonstrated by the detection of early apoptotic cells with fluorescein-labeled Annexin V and increases in cleaved caspase-3 and cleaved PARP protein levels. However, the addition of caspase inhibitor Z-VAD-FMK did not affect growth arrest or apoptosis induction. These results suggest that garcinielliptone G (5) can induce both caspase-3 activation and caspase-independent apoptosis. Therefore, garcinielliptone G (5) may be a potential candidate for acute leukemia treatment.

PARP1 as a Marker of an Aggressive Clinical Phenotype in Cutaneous Melanoma-A Clinical and an In Vitro Study.

(1) Background: Poly(ADP-ribose) polymerase 1) (PARP1) is a pleiotropic enzyme involved in several cellular processes, e.g., DNA damage repair, regulation of mitosis, and immune response. Little is known about the role of PARP1 in melanoma development and progression. We aimed to investigate the prognostic significance of PARP1 expression in cutaneous melanoma through evaluation of mRNA and protein levels of PARP1 in normal melanocytes and melanoma cell lines, as well as in patients’ tissue material from surgical resections. (2) Methods: An in vitro model was based on two types of normal human melanocytes (HEMn-DP and HEMn-LP) and four melanoma cell lines (A375, WM1341D, Hs294T, and WM9). PARP1 mRNA gene expression was estimated using real-time polymerase chain reaction (RT-PCR), whereas the protein level of PARP1 was evaluated by fluorescence confocal microscopy and then confirmed by Western Blotting analysis. The expression of PARP1 was also assessed by immunohistochemistry in formalin-fixed paraffin-embedded tissues of 128 primary cutaneous melanoma patients and correlated with follow-up and clinicopathologic features. (3) Results: The in vitro study showed that melanoma cells exhibited significantly higher PARP1 expression at mRNA and protein levels than normal melanocytes. High PARP1 expression was also associated with the invasiveness of tumor cells. Elevated nuclear PARP1 expression in patients without nodal metastases strongly correlated with significantly shorter disease-free survival (p = 0.0015) and revealed a trend with shorter cancer-specific overall survival (p = 0.05). High PARP1 immunoreactivity in the lymph node-negative group of patients was significantly associated with higher Breslow tumor thickness, presence of ulceration, and a higher mitotic index (p = 0.0016, p = 0.023, and p < 0.001, respectively). In patients with nodal metastases, high PARP1 expression significantly correlated with the presence of microsatellitosis (p = 0.034), but we did not confirm the prognostic significance of PARP1 expression in these patients. In the entire analyzed group of patients (with and without nodal metastases at the time of diagnosis), PARP1 expression was associated with a high mitotic index (p = 0.001) and the presence of ulceration (p = 0.036). Moreover, in patients with elevated PARP1 expression, melanoma was more frequently located in the skin of the head and neck region (p = 0.015). In multivariate analysis, high PARP1 expression was an independent unfavorable prognosticator in lymph node-negative cutaneous melanoma patients. (4) Conclusions: In vitro molecular biology approaches demonstrated enhanced PARP1 expression in cutaneous melanoma. These results were confirmed by the immunohistochemical study with clinical parameter analysis, which showed that a high level of PARP1 correlated with unfavorable clinical outcome. These observations raise the potential role of PARP1 inhibitor-based therapy in cutaneous melanoma.

Revealing Chemopreventive Potential of Active Constituents from Medicinal Herbs Used in Indonesia for (Metastatic) Breast Cancer with Particular Molecular Targets

Breast cancer remains as one of the highest causes of cancer-related deaths in the world, including Indonesia. In spite of following the standard protocol therapy, some patients in developing countries consume medicinal herbs as an alternative, complementary, as well as supportive therapies. Several herbs have been recognized to be used for this purpose. Annona muricata, Curcuma longa, Curcuma zanthorrhiza, Curcuma zedoaria, Phyllanthus urinaria, Gynura procumbens, Garcinia mangostana, Morinda citrifolia, and Nigella sativa are some of the plants used as chemopreventive agents with several formulas. Various types of extracts of Annona muricata show anticancer activities in vitro and in vivo. Curcumin, obtained from Curcuma longa and Curcuma zanthorrhiza, acts as p53 regulator and pro-oxidant in MCF-7 cells and also acts as a fatty acid synthase inhibitor in MDA-MB-231 cells. Xanthorrhizol from Curcuma zanthorrhiza has pro-apoptotic activity via modulation of Bcl-2, p53, and PARP-1 protein levels. Curcuma zedoaria contains curcumenone, curcumenol and curdion, which show pro-apoptotic activity in various cell lines and a cancer-induced mouse model. Corilagin and geraniin from Phyllanthus urinaria have different pro-apoptotic effects, in which, the corilagin-caused apoptotic effect is mediated by extrinsic and mitochondrial pathways, whereas geraniin induces apoptosis via ROS-mediated stimulation, both in MCF-7 cells. Thymoquinone from Nigella sativa has been extensively studied for its anticancer activities in recent years. Plants are cultivated, collected and mixed depending on the use as herbal medicines. Active compounds might be formulated if deemed possible. The development of more potential derivatives is also necessary to produce more optimum anti-cancer agents. In conclusion, Indonesian plants and their active constituents show potential activities to be developed as chemopreventive agents.Keywords: Indonesian medicinal herbs, breast cancer, active constituents, molecular targets

Hypoxia exacerbates cardiomyocyte injury via upregulation of Wnt3a and inhibition of Sirt3

Ischemic injury is a major cause of several cardiovascular diseases, such as myocardial infarction, cardiac hypertrophy, and ventricular remodeling. Using an in vitro hypoxia model to mimic ischemia, we found that hypoxia stimulated Wnt3a expression. A mechanistic study showed that hypoxia-inducible factor 1α (HIF-1α) was directly recruited to the Wnt3a promoter. Wnt3a overexpression significantly decreased cell viability, promoted the generation of apoptotic cells, and enhanced hypoxia-induced injury in neonatal rat cardiomyocytes. This was partially through the upregulation of Caspase-3 mRNA levels and cleaved PARP-1 protein levels. In addition, we observed that Wnt3a exacerbated hypoxia-induced mitochondrial dysfunction and cytosolic release of cytochrome C. Furthermore, we found that Sirt3, a mitochondrial NAD+-dependent deacetylase that modulates mitochondrial metabolism and homeostasis, was negatively regulated by Wnt3a. Conversely, Sirt3 overexpression repressed Wnt3a expression and ameliorated the hypoxia-induced mitochondrial dysfunction. Overall, our findings suggest that the hypoxia–Wnt3a–Sirt3 regulatory axis might be a potential target for cell protection in cardiac ischemia and hypoxia.

Abstract 4085: Blocking Fra-1 sensitises triple-negative breast cancer to olaparib

Abstract Fra-1 (FOSL1), a member of the activator protein 1 (AP-1) transcription factor complex, is overexpressed in triple-negative breast cancer (TNBC) and plays crucial roles in tumor progression and treatment resistance. We have previously identified 118 proteins that interact with endogenous chromatin-bound Fra-1 in TNBC cells in a large screen, and this included PARP1 (Poly (ADP-ribose) polymerase 1). PARP1 inhibitor olaparib is currently in use for treatment of BRCA-mutated TNBC breast cancer. Here, we corroborate that PARP1 interacts with Fra-1, and we also find that PARP1 downregulates Fra-1 and reduces AP-1 transcriptional activity. Inhibition of PARP1, on the other hand, increases Fra-1 levels and enhances AP-1 transcriptional activity. Further, we find that upon inhibition of Fra-1, TNBC cells become sensitized to olaparib treatment. By comparing the Fra-1 and PARP1 regulated transcriptomes with Fra-1 chromatin binding site, we determine that a large fraction of PARP1-regulated genes is dependent on Fra-1. Finally, we show that PARP1 protein levels significantly correlate with Fra-1 in clinical breast cancer tumors, and we identify that while high PARP1 expression is indicative of a poor clinical outcome in breast cancer patients overall, it is not in basal-like tumors. In conclusion, by exploring the functionality of the Fra-1 and PARP-1 interaction, we propose that targeting Fra-1 could serve as a therapeutic approach to improve olaparib treatment outcome for TNBC patients. Citation Format: Dandan Song, Huan He, Indranil Sinha, Linnea Pettersson, Feifei Yan, Lars-Arne Haldosen, Chunyan Zhao, Cecilia Williams. Blocking Fra-1 sensitises triple-negative breast cancer to olaparib [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4085.

Pheophorbide a-mediated sonodynamic, photodynamic and sonophotodynamic therapies against prostate cancer.

Anticancer efficiencies and mechanisms of Pheophorbide-a-mediated photodynamic, sonodynamic and sonophotodynamic therapies were investigated in vitro using androgen-sensitive (LNCaP) and androgen insensitive (PC3) prostate cancer cell lines. The cells were incubated in RPMI-1640 media at various concentrations of Pheophorbide-a. The media was treated with 0.5 W/cm2 ultrasound and/or 0.5 mJ/cm2 light irradiation. Cell proliferation in both cell lines was inhibited most effectively by sonophotodynamic therapy in comparison to that of both monotherapies. LNCaP cells were more sensitive to the applied treatments and the cell survival in LNCaP cell line was observed to be less than that of PC3 cell line. The results of histochemical analysis showed that there were more apoptotic cells in the treatment groups in comparison to control group. Additionally, the treatments induced apoptosis deduced by the overexpressed levels of caspase-3, caspase-8, PARP, and Bax proteins, while the expression levels of caspase-9 and Bcl-2 proteins were observed to be lower than those of control group. Treatments led to an increase in the oxidative stress markers, ROS and MDA, but a decrease in the activities of antioxidant enzymes, SOD, CAT and GSH. The results of this study revealed that Pheophorbide a-mediated sonophotodynamic therapy more efficiently activates the apoptotic mechanisms in prostate cancer cells and thus may provide a promising approach for treatment.

Pregnancy‐associated venous insufficiency course with placental and systemic oxidative stress

The development of lower extremity venous insufficiency (VI) during pregnancy has been associated with placental damage. VI is associated with increased oxidative stress in venous wall. We have investigated potential disturbance/dysregulation of the production of reactive oxygen species (ROS) in placenta and its eventual systemic effects through the measurement of malondialdehyde (MDA) plasma levels in women with VI. A total of 62 women with VI and 52 healthy controls (HCs) were studied. Levels of nicotinamide adenine dinucleotide phosphate‐oxidase 1 (NOX1), 2 (NOX2), inducible nitric oxide synthase (iNOS), endothelial (eNOS), poly(ADP‐ribose) polymerase PARP (PARP) and ERK were measured in placental tissue with immunohistochemistry and RT‐qPCR. Plasma and placental levels of MDA were determined by colorimetry at the two study times of 32 weeks of gestation and post‐partum. Protein and gene expression levels of NOX1, NOX2, iNOS, PARP and ERK were significantly increased in placentas of VI. eNOS activity was low in both study groups, and there were no significant differences in gene or protein expression levels. Women with VI showed a significant elevation of plasma MDA levels at 32 weeks of gestation, and these levels remained elevated at 32 weeks post‐partum. The MDA levels were significantly higher in placentas of women with VI. Placental damage that was found in the women with VI was characterized by overexpression of oxidative stress markers NOX1, NOX2, and iNOS, as well as PARP and ERK. Pregnant women with VI showed systemic increases in oxidative stress markers such as plasma MDA levels. The foetuses of women with VI had a significant decrease in their venous pH as compared to those from HC women. The situation of oxidative stress and cellular damage created in the placenta is in coexpression with the production of a pH acidification.

Combined HER3-EGFR score in triple-negative breast cancer provides prognostic and predictive significance superior to individual biomarkers

Epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 3 (HER3) have been investigated as triple-negative breast cancer (TNBC) biomarkers. Reduced EGFR levels can be compensated by increases in HER3; thus, assaying EGFR and HER3 together may improve prognostic value. In a multi-institutional cohort of 510 TNBC patients, we analyzed the impact of HER3, EGFR, or combined HER3-EGFR protein expression in pre-treatment samples on breast cancer-specific and distant metastasis-free survival (BCSS and DMFS, respectively). A subset of 60 TNBC samples were RNA-sequenced using massive parallel sequencing. The combined HER3-EGFR score outperformed individual HER3 and EGFR scores, with high HER3-EGFR score independently predicting worse BCSS (Hazard Ratio [HR] = 2.30, p = 0.006) and DMFS (HR = 1.78, p = 0.041, respectively). TNBCs with high HER3-EGFR scores exhibited significantly suppressed ATM signaling and differential expression of a network predicted to be controlled by low TXN activity, resulting in activation of EGFR, PARP1, and caspases and inhibition of p53 and NFκB. Nuclear PARP1 protein levels were higher in HER3-EGFR-high TNBCs based on immunohistochemistry (p = 0.036). Assessing HER3 and EGFR protein expression in combination may identify which adjuvant chemotherapy-treated TNBC patients have a higher risk of treatment resistance and may benefit from a dual HER3-EGFR inhibitor and a PARP1 inhibitor.

Sasa quelpaertensis Nakai extract induces p53-independent apoptosis via the elevation of nitric oxide production in human HCT116 colon cancer cells.

Induction of apoptosis in human cancer cells by Sasa quelpaertensis Nakai has been considered to be a potential therapeutic target for cancer treatment; however, the underlying mechanisms of action are not well understood. The present study investigated the role of nitric oxide (NO•) and inhibitors of apoptosis (IAPs) during apoptosis induced by Sasa quelpaertensis Nakai extracts (SQE) in p53-wild type (WT) and p53-null HCT116 colon carcinoma cells. Trypan blue exclusion and Annexin V/propidium iodide assays were used to test for antiproliferation, and apoptosis and cell cycle. Griess and reverse transcription-polymerase chain reaction and western blotting assays were carried out to assay NO• production, and to detect the mRNA and protein levels of Bcl-2, PARP and IAPs. A colorimetric assay was utilized to measure the time-dependent increase in caspase-3 activity. SQE inhibited cell growth and promoted apoptosis by the elevation of NO• in a dose- and time-dependent manner. In addition, both cell types underwent a reduction in mRNA and protein levels of IAPs (survivin, CIAP-1 and -2, and X-linked inhibitor of apoptosis) as well as anti-apoptotic Bcl-2, whereas an increase in protein expression of poly (ADP-ribose) polymerase 1 and caspase 3 activity was observed; however, an equivalent cytotoxic and apoptotic effect by SQE was observed in p53-WT and p53-null cells. Collectively, the results indicated that SQE-induced apoptosis was independent of p53 status and associated with modulation of endogenous NO• and IAP family gene expression.

Gain-of-Function Mutant p53 R273H Interacts with Replicating DNA and PARP1 in Breast Cancer.

Over 80% of triple-negative breast cancers (TNBC) express mutant p53 (mtp53) and some contain oncogenic gain-of-function (GOF) p53. We previously reported that GOF mtp53 R273H upregulates the chromatin association of mini chromosome maintenance (MCM) proteins MCM2-7 and PARP and named this the mtp53-PARP-MCM axis. In this study, we dissected the function and association between mtp53 and PARP using a number of different cell lines, patient-derived xenografts (PDX), tissue microarrays (TMA), and The Cancer Genome Atlas (TCGA) database. Endogenous mtp53 R273H and exogenously expressed R273H and R248W bound to nascent 5-ethynyl-2´-deoxyuridine-labeled replicating DNA. Increased mtp53 R273H enhanced the association of mtp53 and PARP on replicating DNA. Blocking poly-ADP-ribose gylcohydrolase also enhanced this association. Moreover, mtp53 R273H expression enhanced overall MCM2 levels, promoted cell proliferation, and improved the synergistic cytotoxicity of treatment with the alkylating agent temozolomide in combination with the PARP inhibitor (PARPi) talazoparib. Staining of p53 and PARP1 in breast cancer TMAs and comparison with the TCGA database indicated a higher double-positive signal in basal-like breast cancer than in luminal A or luminal B subtypes. Higher PARP1 protein levels and PAR proteins were detected in mtp53 R273H than in wild-type p53-expressing PDX samples. These results indicate that mtp53 R273H and PARP1 interact with replicating DNA and should be considered as dual biomarkers for identifying breast cancers that may respond to combination PARPi treatments. SIGNIFICANCE: p53 gain-of-function mutant 273H and PARP1 interact with replication forks and could serve as potential biomarkers for breast cancer sensitivity to PARP inhibitors. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/3/394/F1.large.jpg.

Multiplex profiling identifies clinically relevant signalling proteins in an isogenic prostate cancer model of radioresistance

The exact biological mechanism governing the radioresistant phenotype of prostate tumours at a high risk of recurrence despite the delivery of advanced radiotherapy protocols remains unclear. This study analysed the protein expression profiles of a previously generated isogenic 22Rv1 prostate cancer model of radioresistance using DigiWest multiplex protein profiling for a selection of 90 signalling proteins. Comparative analysis of the profiles identified a substantial change in the expression of 43 proteins. Differential PARP-1, AR, p53, Notch-3 and YB-1 protein levels were independently validated using Western Blotting. Pharmacological targeting of these proteins was associated with a mild but significant radiosensitisation effect at 4Gy. This study supports the clinical relevance of isogenic in vitro models of radioresistance and clarifies the molecular radiation response of prostate cancer cells.

Abstract NT-118: SEQUENTIAL THERAPEUTIC TARGETING OF OVARIAN CANCER HARBORING DYSFUNCTIONAL BRCA1

Abstract BACKGROUND: Ovarian cancer is the most lethal gynecologic cancer. High grade serous ovarian cancer (HGSC) is the most common and deadly histological subtype. The current standard treatment protocol involves primary debulking surgery followed by platinum-based combination chemotherapy. PARP inhibitors(PARPi) are the first approved personalized treatments used in BRCA1-mutated recurrent ovarian cancer patients and have shown promising clinical results. Previously published data in collaboration with Dr. Witcher's lab, we described a significant reduction in PARP1 protein levels in patients after giving standard carboplatinum-paclitaxel chemotherapy that is effecting the clinical efficacy of PARP inhibitors in clinical trials. PARP inhibitors are currently administered after standard chemotherapy, when PARP levels are the lowest which was clearly shown in the previous published paper. Applying novel strategy and following the sequence of administration, giving PARP inhibitors first followed by standard chemotherapy might improve response rates. This study aims to evaluate this strategy (in vitro) in the pre-clinical models. METHODS: BRCA1 mutated (UWB1.287, SNU-251), epigenetically silenced (OVCAR8), and wild-type BRCA1 (OVCAR3, SKOV3, A2780P &amp; A2780R) cell lines were exposed to clinically relevant doses of PARPi, either followed by standard chemotherapy, or the inverse sequence. Therapeutic efficacy was assessed using colony formation assay. Apoptotic index was evaluated by cell cycle analysis and apoptotic assays using flow cytometry. Western Blotting was used to detect the levels of relevant apoptotic and cell cycle proteins. RESULTS: Exposure to PARPi prior to standard chemotherapy sensitized BRCA1 mutated or epigenetically silenced BRCA1 cell lines to lower doses of Cisplatin (CP) or Paclitaxel (PT). Similarly, pre-treatment with PARPi prior to chemotherapy induced apoptosis more effectively in the same cell lines. Similar results were observed in BRCA1 wild-type cell lines and cell lines in which BRCA1 functionality was restored. CONCLUSION: Pre-treatment of cell lines with PARPi followed by standard chemotherapy is more efficient (in vitro) in inhibiting growth and inducing apoptosis than the present sequence of chemotherapy followed by PARPi. Citation Format: Tahira Baloch, Roy Kessous, David Octeau , Liron Kogan, Ido Laskov, Michael Witcher, Walter H. Gotlieb and Amber Yasmeen. SEQUENTIAL THERAPEUTIC TARGETING OF OVARIAN CANCER HARBORING DYSFUNCTIONAL BRCA1 [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr NT-118.