Cleaved Poly ADP-ribose Polymerase Expression Research Articles

Abstract 5493: Activity of RP12146, a novel, selective, and potent small molecule inhibitor of PARP 1/2, in solid tumors

Abstract Introduction: The Poly (ADP-ribose) polymerase (PARP) family plays an important role in the regulation of transcription, apoptosis and DNA damage response. Several PARP inhibitors have been approved for the treatment of BRCA-mutated ovarian, breast and pancreatic cancer. Through ‘synthetic lethality’, the applicability PARP inhibitors can be expanded to cancers beyond the well-defined BRCA defects either as monotherapy or in combination with established therapy across various solid tumor types. Herein, we describe the efficacy of RP12146 as a single agent and in combination with approved therapies in preclinical models of solid tumors. Methods: Enzymatic potency was evaluated using a PARP Chemiluminescent Activity Assay Kit (BPS biosciences). Cell growth was determined following incubation with RP12146 as a single agent or in combination with approved agents in various solid tumor cell lines. Apoptosis was evaluated following incubation of cell lines with compound for 48 or 72 h, subsequent staining with Annexin-V-PE and 7-AAD, and analysis by flow cytometry. Anti-tumor potential of RP12146 as a single agent or in combination with chemotherapeutic agents was tested in OVCAR-3 and NCI-H69 Xenografts. Expression of downstream PAR, PARP-trapping, and cleaved PARP expression were determined in cell lines and xenograft tumor samples by Western blotting. Plasma and tumor concentration of RP12146 in NCI-H69 xenograft samples were also determined. Results: RP12146 demonstrated equipotent inhibition of PARP1 (0.6 nM) and PARP2 (0.5 nM) with several fold selectivity over the other members of the PARP family. Compound caused a dose-dependent growth inhibition of both BRCA mutant and non-mutant cancer cell lines with GI50 in the range of 0.04 µM to 9.6 µM. Combination of RP12146 with Temozolomide, Topotecan, Lurbinectedin, and Abemaciclib demonstrated either additive or synergistic effects manifested by an inhibition in growth of solid tumor cell lines. RP12146 exhibited anti-tumor potential with TGI of 28% and 21.8% as a single agent in OVCAR-3 and NCI-H69 Xenograft model respectively. In NCI-H69 xenograft model, RP12146 in combination with cisplatin exhibited TGI of 69.3 %. Conclusion: Data demonstrate the therapeutic potential of RP12146 as single agent and in combination in solid tumors. RP12146 is currently being evaluated in Phase 1 clinical trials in patients with locally advanced or metastatic solid tumors (NCT05002868). Citation Format: Srikant Viswanadha, Satyanarayana Eleswarapu, Kondababu Rasamsetti, Haritha Polimati, Sridhar Veeraraghavan, Swaroop Vakkalanka. Activity of RP12146, a novel, selective, and potent small molecule inhibitor of PARP 1/2, in solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5493.

Abstract 1233: Preclinical profile of RP12146, a novel, selective, and potent small molecule inhibitor of PARP1/2

Abstract Background: Poly (ADP-ribose) polymerase (PARP) activity involves synthesis of Poly-ADP ribose (PAR) polymers that recruit host DNA repair proteins leading to correction of DNA damage and maintenance of cell viability. Upon combining with DNA damaging cytotoxic agents, PARP inhibitors have been reported to demonstrate chemo- and radio-potentiation albeit with incidences of myelosuppression. A need therefore exists for the development selective PARP1/2 inhibitors with a high therapeutic window to fully exploit their potential as a single agent or in combination with established therapy across various tumor types. Additionally, with the emerging concept of ‘synthetic lethality', the applicability PARP inhibitors can be expanded to cancers beyond the well-defined BRCA defects. Herein, we describe the preclinical profile of RP12146, a novel and selective small molecule inhibitor of PARP1 and PARP2. Methods: Enzymatic potency was evaluated using a PARP Chemiluminescent Activity Assay Kit (BPS biosciences). Cell growth was determined following incubation with RP12146 in BRCA1 mutant and wild-type cell lines across indications. Apoptosis was evaluated following incubation of cell lines with compound for 120 h, subsequent staining with Annexin-V-PE and 7-AAD, and analysis by flow cytometry. For cell cycle, cells were incubated with compound for 72 h, and stained with Propidium Iodide prior to analysis by flow cytometry. Expression of downstream PAR, PARP-trapping, phospho-γH2AX and cleaved PARP expression were determined in UWB1.289 (BRCA1 null) cells by Western blotting. Anti-tumor potential of RP12146 was tested in OVCAR-3 Xenograft model. Pharmacokinetic properties of the molecule were also evaluated. Results: RP12146 demonstrated equipotent inhibition of PARP1 (0.6 nM) and PARP2 (0.5 nM) with several fold selectivity over the other members of the PARP family. Compound caused a dose-dependent growth inhibition of both BRCA mutant and non-mutant cancer cell lines with GI50 in the range of 0.04 µM to 9.6 µM. Incubation of UWB1.289 cells with RP12146 caused a G2/M arrest with a corresponding dose-dependent increase in the percent of apoptotic cells. Expression of PAR was inhibited by 86% at 10 nM with a 2.3-fold increase in PARP-trapping observed at 100 nM in presence of RP12146. A four-fold increase in phospho-γH2AX and > 2-fold increase in cleaved PARP expression was observed at 3 µM of the compound. RP12146 exhibited anti-tumor potential with TGI of 28% as a single agent in OVCAR-3 xenograft model. Efficay was superior compared to Olaparib tested at an equivalent dose. Pharmacokinetic studies in rodents indicated high bioavailability with favorable plasma concentrations relevant for efficacy Conclusions: Data demonstrate the therapeutic potential of RP12146 in BRCA mutant tumors. Testing in patients is planned in H1 2021. Citation Format: Srikant Viswanadha, Satyanarayana Eleswarapu, Kondababu Rasamsetti, Debnath Bhuniya, Gayatriswaroop Merikapudi, Sridhar Veeraraghavan, Swaroop Vakkalanka. Preclinical profile of RP12146, a novel, selective, and potent small molecule inhibitor of PARP1/2 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1233.

Licochalcone A induces apoptotic cell death via JNK/p38 activation in human nasopharyngeal carcinoma cells.

Licochalcone A is widely studied in different fields and possesses antiasthmatic, antibacterial, anti-inflammatory, antioxidative, and anticancer properties. Its antimalignancy activity on renal, liver, lung, and oral cancer has been explored. However, limited studies have been conducted on the inhibitory effects of licochalcone A in human nasopharyngeal carcinoma cells. We determined cell viability using MTT assay. Cell cycle distribution and apoptotic cell death were measured via flow cytometry. Caspase activation and mitogen-activated protein kinase-related proteins in nasopharyngeal cancer cells in response to licochalcone A were identified by Western blot analysis. Results indicated that licochalcone A reduces cell viability and induces apoptosis, as evidenced by the upregulation of caspase-8 and caspase-9, caspase-3 activation, and cleaved-poly ADP-ribose polymerase expression. Treatment with licochalcone A significantly increases ERK1/2, p38, and JNK1/2 activation. Co-administration of a JNK inhibitor (JNK-IN-8) or p38 inhibitor (SB203580) abolishes the activation of caspase-9, caspase-8, and caspase-3 protein expression during licochalcone A treatment. These findings indicate that licochalcone A exerts a cytostatic effect through apoptosis by targeting the JNK/p38 pathway in human nasopharyngeal carcinoma cells. Therefore, licochalcone A is a promising therapeutic agent for the treatment of human nasopharyngeal cancer cells.

Implications of alpha-synuclein nitration at tyrosine 39 in methamphetamine-induced neurotoxicity in vitro and in vivo.

Methamphetamine is an amphetamine-type psychostimulant that can damage dopaminergic neurons and cause characteristic pathological changes similar to neurodegenerative diseases such as Parkinson's disease. However, its specific mechanism of action is still unclear. In the present study, we established a Parkinson's disease pathology model by exposing SH-SY5Y cells and C57BL/6J mice to methamphetamine. In vitro experiments were performed with 0, 0.5, 1.0, 1.5, 2.0 or 2.5 mM methamphetamine for 24 hours or 2.0 mM methamphetamine for 0-, 2-, 4-, 8-, 16-, and 24-hour culture of SH-SY5Y cells. Additional experimental groups of SH-SY5Y cells were administered a nitric oxide inhibitor, 0.1 mM N-nitro-L-arginine, 1 hour before exposure to 2.0 mM methamphetamine for 24 hours. In vivo experiments: C57BL/6J mice were intraperitoneally injected with N-nitro-L-arginine (8 mg/kg), eight times, at intervals of 12 hours. Methamphetamine 15 mg/kg was intraperitoneally injected eight times, at intervals of 12 hours, but 0.5-hour after each N-nitro-L-arginine injection in the combined group. Western blot assay was used to determine the expression of nitric oxide synthase, α-synuclein (α-Syn), 5G4, nitrated α-synuclein at the residue Tyr39 (nT39 α-Syn), cleaved caspase-3, and cleaved poly ADP-ribose polymerase (PARP) in cells and mouse brain tissue. Immunofluorescence staining was conducted to measure the positive reaction of NeuN, nT39 α-Syn and 5G4. Enzyme linked immunosorbent assay was performed to determine the dopamine levels in the mouse brain. After methamphetamine exposure, α-Syn expression increased; the aggregation of α-Syn 5G4 increased; nT39 α-Syn, nitric oxide synthase, cleaved caspase-3, and cleaved PARP expression increased in the cultures of SH-SY5Y cells and in the brains of C57BL/6J mice; and dopamine levels were reduced in the mouse brain. These changes were markedly reduced when N-nitro-L-arginine was administered with methamphetamine in both SH-SY5Y cells and C57BL/6J mice. These results suggest that nT39 α-Syn aggregation is involved in methamphetamine neurotoxicity.

Anti-tumor effects of bakuchiol on human gastric carcinoma cell lines are mediated through PI3K/AKT and MAPK signaling pathways

Bakuchiol is extracted from Psoraleacorylifolia, a member of the Leguminosae family, has been used in Indian Ayurvedic and Chinese traditional medicine, and it possesses an anticancer effect. The primary aim of the present study was to identify the molecular mechanisms underlying the anticancer effect of bakuchiol monoterpenes. Bakuchiol treatment significantly inhibited NUGC3 human gastric cancer cell viability in a concentration dependent manner. In addition, bakuchiol significantly increased the apoptotic cell population in the sub‑G1 phase, and Annexin‑V‑fluorescein isothiocyanate/propidium iodide double staining confirmed the increase in apoptosis. Nuclear fragmentation and the formation of apoptotic organelles were promoted in bakuchiol‑treated NUGC3 cells. Western blotting results indicated that bakuchiol treatment significantly decreased procaspase‑3,6,8,9 and poly (ADP‑ribose) polymerase (PARP) expression levels, increased cleaved caspase‑3 and cleaved PARP expression levels, and increased the B cell lymphoma‑2 associated X, apoptosis regulator:B cell lymphoma‑extra large ratio. Bakuchiol‑treated NUGC3 cells demonstrated significantly reduced phosphorylated (p‑) protein kinase B (AKT) protein expression levels and elevated p‑extracellular signal related kinase 1/2 (ERK1/2), p‑c‑Jun N‑terminal kinase (JNK) and p‑p38. Bakuchiol‑induced cell death was mitochondrial dependent, through modulation of phosphoinositide 3‑kinase/AKT and mitogen‑activated protein kinase signaling pathways. These findings demonstrated that bakuchiol possesses potential for treating human gastric cancer.

Osthole induces apoptosis and suppresses proliferation via the PI3K/Akt pathway in intrahepatic cholangiocarcinoma.

Osthole is a natural coumarin isolated from Umbelliferae plant monomers. Previous research has indicated that osthole exerts a wide variety of biological effects, acting as anti-seizure, anti-osteoporosis and anti-inflammation. However, the regulatory effect and related molecular mechanism of osthole in intrahepatic cholangiocarcinoma (ICC) remain unknown. In the present study, the authors found that osthole inhibited ICC cell lines in a dose- and time-dependent manner. Osthole also significantly induced mitochondrial-dependent apoptosis by upregulating Bax, cleaved caspase-3, cleaved caspase-9, and cleaved poly ADP-ribose polymerase expression, and by downregulating Bcl-2 expression. Moreover, the levels of p-Akt and PI3K were significantly decreased, while total Akt protein levels were unchanged. Following transfection with wild-type-Akt and constitutively active (CA)-Akt plasmids, the effects of osthole were decreased. Osthole was also able to suppress tumor growth in vivo. Together, these data demonstrated that osthole induces mitochondrial-dependent apoptosis via the PI3K/Akt pathway, suggesting that osthole may represent a novel and effective agent for the treatment of ICC.

Casticin induces apoptosis and G0/G1 cell cycle arrest in gallbladder cancer cells

BackgroundCasticin, the flavonoid extracted from Vitex rotundifolia L, exerts various biological effects, including anti-inflammatory and anti-cancer activity. The aim of this study is to investigate the effects and mechanisms of casticin in human gallbladder cancer cells.MethodsHuman NOZ and SGC996 cells were used to perform the experiments. CCK-8 assay and colony formation assay were performed to evaluate cell viability. Cell cycle analyses and annexin V/PI staining assay for apoptosis were measured using flow cytometry. Western blot analysis was used to evaluate the changes in protein expression, and the effect of casticin treatment in vivo was experimented with xenografted tumors.ResultsIn this study, we found that casticin significantly inhibited gallbladder cancer cell proliferation in a dose- and time-dependent manner. Casticin also induced G0/G1 arrest and mitochondrial-related apoptosis by upregulating Bax, cleaved caspase-3, cleaved caspase-9 and cleaved poly ADP-ribose polymerase expression, and by downregulating Bcl-2 expression. Moreover, casticin induced cycle arrest and apoptosis by upregulating p27 and downregulating cyclinD1/cyclin-dependent kinase4 and phosphorylated protein kinase B. In vivo, casticin inhibited tumor growth.ConclusionCasticin induces G0/G1 arrest and apoptosis in gallbladder cancer, suggesting that casticin might represent a novel and effective agent against gallbladder cancer.

Basic helix-loop-helix transcription factor DEC1 regulates the cisplatin-induced apoptotic pathway of human esophageal cancer cells.

DEC1 [basic helix-loop-helix (BHLH) E40/Stra13/Sharp2] and DEC2 (BHLHE41/Sharp1) are BHLH transcription factors that are associated with the regulation of apoptosis, cell proliferation, and circadian rhythms, as well as malignancy in various cancers. However, the roles of DEC1 and DEC2 expression in esophageal cancer are poorly understood. In this study, we examined the roles of DEC1 and DEC2 in human esophageal cancer TE 5 and TE 10 cells that had been treated with cis-diamminedichloroplatinum (II) (cisplatin: CDDP). Expression of DEC1 and DEC2 was decreased with CDDP treatment in TE 5 cells; however, knockdown or overexpression of DEC1/DEC2 had little effects on CDDP-induced apoptosis in TE 5 cells. DEC1 expression was up-regulated in CDDP-treated TE 10 cells, whereas DEC2 expression was unchanged. DEC1 knockdown by siRNA in TE 10 decreased the amount of cleaved poly (ADP-ribose) polymerase (PARP) after treatment with CDDP, whereas DEC2 knockdown had no effects on the amount of cleaved PARP in both the presence and absence of CDDP. We also demonstrated that DEC1 overexpression promoted cleaved PARP expression, whereas DEC2 overexpression had no effects on the amount of cleaved PARP in TE 10 cells. These results suggested that DEC1 has pro-apoptotic effects on human esophageal cancer TE 10 cells of well-differentiated type.

Transplantation of olfactory ensheathing cells attenuates acute carbon monoxide poisoning-induced brain damages in rats.

In this study, the therapeutic effect of olfactory ensheathing cells (OEC) transplantation on brain damage was evaluated on acute carbon monoxide (CO) poisoning rat model. Two weeks after primary culture, OECs were microinjected into hippocampus of CO poisoning rats. Survival of OECs in the host was observed and quantified. OECs survived at 2 weeks, but surviving cell number was found sharply decreased at 6 weeks and reduced to less than 10(3) at 8 weeks after transplantation. At 2 weeks after transplantation, motor function test and cerebral edema assay were performed and followed by pathological examination including hematoxylin and eosin and immunohistochemistry staining to observe the neuron injury and synapsin I and growth associated protein-43 (GAP-43) expression. Furthermore, biomarkers of oxidative stress and apoptosis related proteins in the hippocampus were detected. The results showed that CO exposure led to neurological dysfunction and cerebral edema in rats. After OEC transplantation, neurological function was significantly improved and the cerebral edema was alleviated. In addition, the numbers of neurons and Nissl bodies were increased and synapsin I and GAP-43 protein expressions were upregulated in the hippocampus. Compared with CO poisoned rats, superoxide dismutase activity and glutathione content were both increased and methane dicarboxylic aldehyde level was decreased in the hippocampus of OEC transplanted rats. Moreover, OEC transplantation reduced apoptosis induced by CO exposure. The Bcl-2 expression was significantly upregulated and Bax expression was significantly downregulated. The activity of caspase-3 and the cleaved-poly ADP-ribose polymerase expression were decreased. Taken together, our data suggest that OEC attenuates brain damages induced by acute CO poisoning within 2 weeks after transplantation.

Ampelopsin induces apoptosis by regulating multiple c-Myc/S-phase kinase-associated protein 2/F-box and WD repeat-containing protein 7/histone deacetylase 2 pathways in human lung adenocarcinoma cells.

Ampelopsin (AMP), a plant flavonoid, has been reported to inhibit cell growth and/or induce apoptosis in various types of tumor. The aim of the present study was to assess the apoptosis-inducing activity of AMP in A549 human lung adenocarcinoma epithelial cells and the associated underlying mechanism. A549 cells were incubated with different concentrations of AMP in culture medium. Cell growth and apoptosis were evaluated by MTT assay and Annexin V/propidium iodide double staining and flow cytometry, respectively. In addition, western blotting and reverse transcription quantitative polymerase chain reaction analysis were used to examine the time-dependent changes in protein expression. Certain changes in apoptotic protein expression were detected following exposure to AMP, including X-linked inhibitor of apoptosis protein release, reduced B-cell lymphoma 2, myeloid cell leukemia 1 and survivin expression levels, increased Bcl-2-associated X protein expression levels and cleaved-poly ADP ribose polymerase expression. The results revealed that AMP was a potent inhibitor of A549 cell proliferation. The c-Myc/S-phase kinase-associated protein 2 (Skp2) and histone deacetylase (HDAC)1/2 pathways were found to exert an important role in AMP-induced A549 cell apoptosis, as increased levels of c-Myc mRNA and reduced levels of c-Myc/Skp2 and HDAC1 and 2 proteins following AMP treatment were observed. The levels of F-box and WD repeat-containing protein 7α (Fbw7α), Fbw7β, Fbw7γ, phosphorylated-(p−)c-Myc (Thr58) and glycogen synthase kinase 3β (GSK3β) proteins involved in c-Myc ubiquitin-dependent degradation were also analyzed. Following exposure to AMP, the expression levels of Fbw7α, Fbw7γ and GSK3β were reduced and p-c-Myc (Thr58) expression levels were increased. The results suggest that AMP exerts an anticancer effect, which is associated with the degradation of c-Myc, Skp2 and HDAC1 and 2. The ability of AMP to induce apoptosis independently of Fbwα and Fbw7γ suggests a possible use in drug-resistant cancer associated with Fbw7 deficiency. Understanding the exact underlying mechanism requires further investigation of the association between c-Myc and Fbw7α/γ reversal, and analysis of whether Thr58 phosphorylation of c-Myc is dependent on GSK3β.

Synergistic effects of ethyl acetate fraction of Ficus septica Burm. f. and doxorubicin chemotherapy on T47D human breast cancer cell line

Previously, ethanolic extract of Ficus septica Burm. f. (Moraceae) leaves and its ethyl acetate soluble fraction (EASF) exhibited potent cytotoxic effects on T47D breast cancer cells. In the present study, we further investigated the effects of EASF of ethanolic extract of F. septica leaves in combination with doxorubicin on T47D breast cancer cell line in cytotoxicity, cell cycle arrest and apoptosis induction. The cytotoxic effect analysis on T47D cells was carried out using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Analysis of cell cycle distribution was performed using a flowcytometer and the data were analyzed using ModFit LT 3.0 program. Apoptosis assay was carried out by double staining method using ethidium bromide-acridin orange. The expression of cleaved-poly ADP-ribose polymerase in the T47D cell line was identified using immunohistochemical techniques. The combination of doxorubicin (2 to 8 nmol/L) with EASF (0.875 to 7 μg/mL) more potently inhibited cell growth than the single treatment of doxorubicin in T47D cells. In addition, the combination of doxorubicin and EASF could increase the incidence of cells undergoing apoptosis. EASF was found to improve cytotoxic effect of doxorubicin by changing the inhibition of cell cycle G(2)/M to G(1) phase. The combination also exhibited a more intensive stimulatory effect on cleaved-PARP expression in T47D cells than the single treatment. It is concluded that EASF may enhance doxorubicin activities in T47D cells by inducing apoptosis and cell cycle arrest.

SB939 efficiently induce breast cell lines cycle arrest and apoptosis and the mechanism

Objective To investigate the effects of SB939,a potent histone deacetylase (HDAC)inhibitor,on proliferation,cycle arrest and apoptosis of breast cancer cell lines T47D and MDA-MB-231 in vitro and its potential regulating mechanism.Methods Cells were treated with different concentrations of SB939.Cell proliferation was measured by using methyl thiazol tetrazolium (MTT) assay.Cell cycle rate was examined by proliferation index (PI) staining.Apoptotic rate of cells were detected by Annexin V/PIdouble-staining.The expression of proteins,such as poly ADP-ribose polymerase (PARP),were analyzed by Western blotting.The mRNA level of p21 and Cyclin B1 were detected by Real-time polymerase chain reaction (Real-time PCR).Results Along with the increase of SB939 concentration,the inhibition of SB939 on T47D and MDA-MB-231 cell proliferation were obvious enhancement 50％ inhibitory concentration ( IC50 ) were (2.721 ± 0.320 ),(5.647 ± 0.470) μmol/L; Flow cytometry showed cells in G2/M phase significantly increased ( P＜0.05).After cells exposed to SB939 ( 1 μmol/L) for 24 h,G2/Mphase rates were ( 21.20 ± 1.90 ) ％,( 28.35 ± 2.25 ) ％.The rates of apoptotic cells were ( 37.60 ±1.34 ) ％,( 34.40 ± 1.77 ) ％,significantly increased as compared to the control cells ( P ＜ 0.05 ); Western blotting showed that the expression of cleaved PARP,bax and p21 were increased while B lymphocytes/leukemia-2 ( bcl-2),cdc2,Cyclin B 1 were down-regulated; The Real-time PCR suggested that the relative mRNA level of p21 was increased and Cyclin B1 was decreased.Conclusion SB939 in vitro can significantly inhibit proliferation,induce cell cycle arrest and apoptosis on breast cancer cell lines,which was in a dose-dependent manner. Key words: Breast Neoplasms; Cell cycle; Apoptosis

Effect of celecoxib, a specific cyclooxygenase 2 inhibitor, on the apoptotic and mitotic indexes of breast cancer in patients with early stage disease

14132 Background: To assess whether the administration of celecoxib, a specific cyclooxegenease-2 (COX-2) inhibitor, to patients with breast cancer alters the proliferative and apoptotic indexes of their tumors. Methods: Women newly diagnosed with non metastatic breast cancer were enrolled into the study after undergoing a diagnostic core needle biopsy. Patients received celecoxib treatment at 400 mg orally twice a day for 14 days, and then underwent surgical excision of their tumor. Core biopsies obtained at the time of initial diagnostic procedure and surgical excision specimens were stained for Ki-67, as well as COX-2 and cleaved poly (ADP-ribose) polymerase (PARP) expression (as an apoptosis marker). Appropriate negative and positive controls were included. We assessed the difference in Ki- 67, COX-2 and cleaved PARP expression levels, before and after treatment using the Wilcoxon’s matched-pair ranks test and the McNemar’s test. Results: 16 patients were enrolled. The median age was 54.6 years. ER and/or PR expression was present in 81% of tumors; Her-2 neu overexpression was present in 25%. No significant change in COX-2 or cleaved PARP expression was noticed in the post intervention specimen compared to the core biopsies. Surprisingly, there was a significant increase in the Ki-67 expression (p < 0.009). Conclusions: we have conducted a short term prospective study to assess the effects of celecoxib, on the proliferative and apoptotic indexes in patients with early stage breast cancer. We have found an increase in the Ki-67 activity, with no significant down regulation of COX-2 or increase in cleaved PARP expression with 14 days of therapy. This could be partly due to the small sample size. [Table: see text]

Sex hormone modulation of cell growth and apoptosis of the human monocytic/macrophage cell line

Sex hormones seem to modulate the immune/inflammatory responses by different mechanisms in female and male rheumatoid arthritis patients. The effects of 17β-oestradiol and of testosterone were tested on the cultured human monocytic/macrophage cell line (THP-1) activated with IFN-γ in order to investigate their role in cell proliferation and apoptosis. Activated human THP-1 cells were cultured in the presence of 17β-oestradiol and testosterone (final concentration, 10 nM). The evaluation of markers of cell proliferation included the NF-κB DNA-binding assay, the NF-κB inhibition complex, the proliferating cell nuclear antigen expression and the methyl-tetrazolium salt test. Apoptosis was detected by the annexin V-propidium assay and by the cleaved poly-ADP ribose polymerase expression. Specific methods included flow analysis cytometry scatter analysis, immunocytochemistry and western blot analysis. Cell growth inhibition and increased apoptosis were observed in testosterone-treated THP-1 cells. Increased poly-ADP ribose polymerase-cleaved expression and decreased proliferating cell nuclear antigen expression, as well as an increase of IκB-α and a decrease of the IκB-α phosphorylated form (ser 32), were found in testosterone-treated THP-1 cells. However, the NF-κB DNA binding was found increased in 17β-oestradiol-treated THP-1 cells. The treatment with staurosporine (enhancer of apoptosis) induced decreased NF-κB DNA binding in all conditions, but particularly in testosterone-treated THP-1 cells. Treatment of THP-1 by sex hormones was found to influence cell proliferation and apoptosis. Androgens were found to increase the apoptosis, and oestrogens showed a protective trend on cell death – both acting as modulators of the NF-κB complex.

Expression of pro-inflammatory cytokine and caspase genes promotes neuronal apoptosis in pontine reticular formation after spinal cord transection

We identified apoptotic neurons in pontine reticular formation (PRF), the origin of pontine reticulospinal fibers, in adult Sprague-Dawley rats after complete spinal cord transection (SCT) at T8 level. SCT also increased the expression in PRF of tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta, IL-6, caspase-1, or caspase-3 mRNA. This was followed by an augmented expression of activated caspase-3 protein, an increase in caspase-3 activity, and expression of a cleaved fragment of poly(ADP-ribose) polymerase (PARP), a proteolytic substrate of the activated caspase-3. Microinjection bilaterally into the PRF of an antiserum against TNF-alpha attenuated the expression of IL-6 mRNA and up-regulation of caspase-3 mRNA, and a caspase-3 inhibitor, DEVD-CHO, suppressed the augmentation in activated caspase-3 or cleaved PARP expression after SCT. Both treatments also reduced the number of SCT-induced apoptotic PRF neurons. We conclude that PRF neurons in adult mammalian brain may actively degrade themselves after SCT through apoptosis, via signaling processes that involve activation of proinflammatory cytokine genes and the intracellular caspase-3 pathway.

Cleaved caspase-3, caspase-7 and poly (ADP-ribose) polymerase are complementarily but differentially expressed in human medulloblastomas

Expression of cleaved caspase-3, cleaved caspase-7 and specific product of caspase-dependent Poly (ADP-Ribose) Polymerase (PARP) cleavage have been examined by immunohistochemistry in seven human medulloblastomas. Cleaved caspase-3 and cleaved PARP expression parallels apoptosis as revealed with classical morphological criteria and with the method of in situ end-labelling of nuclear DNA fragmentation. Cleaved PARP co-localizes cleaved caspase-3 in the majority of tumors and areas thus indicating that caspase-3 is a major effector caspase leading to apoptosis in these tumors. Yet cleaved caspase-7 was also expressed in a small number of cells in four of seven tumors, but was the predominant caspase associated with cleaved PARP in one medulloblastoma. These findings indicate that effector caspase-3 and -7 may act in association, although caspase-7 may be exceptionally dominant in selected tumors.