Sputum Autoantibodies Are More Relevant in Autoimmune Responses in Asthma than Are Serum Autoantibodies

PURPOSE: The data on the differences between sputum autoantibodies (Sp-Abs) and serum autoantibodies (Se-Abs) in reflection of autoimmune responses to lungs is still lacking. METHODS: Ten types of Abs were investigated in matched Se and Sp samples collected from recruited subjects. Correlations between Ab levels and airway inflammatory parameters and measures of pulmonary function were assessed. The network-based and inter-correlated analysis was performed to explore the patterns of Sp- and Se-Ab profiles. RESULTS: Fifty stable asthmatic patients and 24 healthy volunteers were recruited for our study, 15 with mild asthma, 18 with moderate asthma and 17 with severe asthma. The concentrations of Sp-Ab against U1 small nuclear ribonucleoprotein (Sp-anti-U1-SnRNP), Sp-Ab against Smith antigen and Se-Ab against thyroid peroxidase (anti-TPO) in severe asthmatics and Sp-anti-U1-SnRNP in moderate asthmatics were significantly higher compared to healthy controls and mild asthmatic subjects (P < 0.05). Sp-anti-U1-SnRNP levels were positively correlated with the dose of inhaled corticosteroids, Sp eosinophil counts and fractional exhaled nitric oxide (r = 0.326, P = 0.022; r = 0.356, P = 0.012; r = 0.241, P = 0.025, respectively) and negatively correlated with Sp neutrophil counts (r = −0.308, P = 0.031) with adjustment for age. Spearman's correlation matrix showed multiple inter-correlations among Sp-Abs and Se-Abs (P < 0.05) while only the levels of Ab against DNA topoisomerase and anti-TPO in Se were correlated with those Sp-Ab counterparts (P < 0.05). The network-based analysis defined 2 clusters: clusters 1 and 2 contained 10 Sp-Abs and 10 Se-Abs, respectively. CONCLUSIONS: This study observes that Sp-Abs are more associated with clinical parameters and the severity of disease in asthma compared to Se-Abs. Targeting on Sp-Abs which are the hallmark of the localized autoimmune event might help us better understand the role of autoimmunity in the pathological mechanism of asthma.

Correlation between the Expression of Topo I la and Ki67 in Breast Cancer and its clinical Pathological characteristics

Objective: To investigate the expression of Topo Ha and Ki67 and its clinical significance

Methods: The clinical pathological data of one hundred and sixteen invasive breast cancer patients who were admitted into our hospital from July 2013 to December 2015 and underwent radical mastectomy were retrospectively analyzed. The expression of topoispmerase [Topo] lla and Ki67 was detected using immunohistochemical method, and the correlation between the two kinds of proteins and the general clinical pathological characteristics of the patients was analyzed

Results: The positive expression rates of Topo Ha and Ki67 in breast cancer were 58.6% and 75% respectively

The expression of Topo lla was in no apparent correlation with the age, tumor size, estrogen receptor [ER], progesterone receptor [PR] and human epidermal growth factor receptor 2 [HER-2] [P>0.05], but in a correlation with the number of metastatic lymph glands [P<0.05]. The expression of Ki67 was in no apparent correlation with the age, tumor size, EP and HER-2, but in a correlation with the number of metastatic lymph glands and PR [P<0.05]. The multi-factor logistic regression analysis results suggested that the number of metastatic lymph glands was the independent predictive factor of Topo lla positive expression and the number of metastatic lymph glands and PR protein expression state are the independent predictive factors of Ki67 positive expression

Conclusion: Topo lla and Ki67 can be regarded as the indicators for reflecting the proliferation activity of tumor cells, and the detection of Topo lla and Ki67 expression is of great significance to the prognosis evaluation of breast cancer patients and clinical treatment

Estudo da regulação das DNA Estudo da regulação das DNA topoisomerases durante o desenvolvimento de resistência ao etoposídeo e do papel antitumoral de novos compostos em leucemias agudas / DNA topoisomerases's regulation study during resistance development toetoposide and antitumor role of new compounds in acute leukemias

Entre as neoplasias hematológicas, as leucemias agudas configuram o maior número de mortes a cada ano. A quimioterapia para estas neoplasias envolve inibidores de topoisomerase, como as antraciclinas, associados a outros fármacos. Entretanto, alguns pacientes não respondem ao tratamento devido ao desenvolvimento do fenótipo de resistência a múltiplas drogas (MDR), considerada a principal causa de refratariedade e falha no tratamento. Devido à alta taxa de proliferação celular, os tumores super expressam as DNA topoisomerases I e IIα humana (hTopo I e IIα), tornando essas enzimas bons alvos para o desenvolvimento de novos fármacos. Neste contexto, a procura por novos compostos capazes de aumentar a taxa de sobrevida global em pacientes com leucemias agudas e que sejam eficazes em células com fenótipo MDR se faz necessária. Os objetivos deste trabalho foram: a)desenvolver linhagens celulares de leucemias agudas resistentes ao etoposido (VP-16); b)caracterizar o fenótipo de resistência, mediado por alterações nas enzimas hTopo I e IIα; c)avaliar o mecanismo de ação dos novos compostos LQBs (LQB-118, -192, -223, -266, -268 e -326) e ácido pomólico (PA), como potenciais inibidores de hTopo I e/ou IIα; e d)investigar a atividade antitumoral dos compostos mais promissores nas linhagens de leucemias agudas resistentes em comparação às parentais. Foi demonstrado que dentre os compostos LQBs avaliados apenas LQB-118 e LQB-223 foram efetivos e específicos em inibir hTopoIIα. PA demonstrou ser um composto dual inibindo hTopo I e IIα. Os três compostos ativos não intercalam no DNA e atuam como inibidores catalíticos, não apresentando afinidade de interação ao sítio de ligação entre o DNA e camptotecina ou VP-16. Os estudos de modelagem molecular também sugeriram que LQB-118 e LQB-223 apresentam alta afinidade de ligação à região ATPase de hTopoIIα...

Acute leukemias represent the largest number of annual deaths from hematologic malignancy. The chemotherapy for these neoplasms involves topoisomerase inhibitors, such as anthracyclines, associated with other drugs. However, some patients do not respond to this treatment scheme because of the development of multiple drug resistance (MDR) phenotype.MDR phenotype is the main cause of refractoriness and treatment failure in acute leukemias. Due to the high rate of cell proliferation, tumors overexpress human DNA topoisomerases I and IIα (hTopo I and IIα), leading these enzymes as good targets for the development of new anticancer drugs. In this context, the searching for novel compounds capable of increase theoverall survival rate in patients with acute leukemias and be effective on cells with MDR phenotype is urgent. The objectives of this research are: a) todevelop acute leukemia cell linesresistant to etoposide (VP-16); b) to characterize the resistance phenotype mediated by changes on hTopo I and IIα; c) to evaluate themechanism of action of new compounds LQBs(LQB-118, -192, -223, -266, -268 and -326) and pomolic acid (PA), as potential inhibitors of hTopo I and/or IIα; and d) to investigate the antitumor activity of the most promising compounds on parental or resistant acute leukemia cell lines. It was demonstrated that among the LQBs evaluated only LQB-118 and LQB-223 were effective and specific to hTopo IIα and that PA inhibited both hTopo I and IIα. They did not intercalate into DNA and acted as catalytic inhibitors with poor affinity to interact with camptothecin or VP-16 biding site. The molecular modeling studies also suggested that LQB-118 and LQB-223 presented a high affinity to bindto ATPase region of hTopo IIα. Acute lymphoid CEM-R and myeloid leukemia U937-R cell lines were developed by exposition to increasing concentrations of VP-16...

Comparing the expression of human DNA topoisomerase I in KM71H and X33 strains of Pichia pastoris

Background: Human is an essential cellular enzyme that is found in all human cells. As this enzyme is upregulated in cancer cells exceedingly, it is used as a target for cancer chemotherapeutic drug development. As such, producing the in-house enzyme for the purpose to speed up the search for more cost-effective and target specific hTopoI inhibitors is warranted. This study aims to compare the optimised conditions for the expression of hTopoI in KM71H (MutS) and X33 (Mut+) strains of Pichia pastoris. P. pastoris transfected with an hTopoI recombinant vector was used for the optimization of a higher level of hTopoI expression. Results: In the process, fed-batch cultivation parameters that influence the expression of hTopoI, such as culture temperature, methanol induction and feeding strategy, were optimised in the transfected KM71H and X33 P. pastoris strains in a shake flask system. The cell density and total protein concentration (protein level) of transfected P. pastoris were compared to determine the optimum culture conditions for each transfected P. pastoris strain. A higher hTopoI level was observed in the transfected KM71H culture supernatant (2.26 ng/mL) when the culture was incubated in the optimum conditions. Conclusions: This study demonstrated that MutS strain (KM71H) expressed and secreted a higher level of hTopoI heterologous protein in the presence of methanol compared to the Mut+ strain; X33 (0.75 ng/mL). However, other aspects of optimization, such as pH, should also be considered in the future, to obtain the optimum expression level of hTopoI in P. pastoris.

Inhibitory effect of galangin on DNA topoisomerases in lung cancer cells / 中南大学学报(医学版)

OBJECTIVE@#To explore the eff ect of galangin on DNA topoisomerases in lung cancer cells A549 and H46 as well on cell growth.@*METHODS@#The inhibitory effect of galangin on the growth of A549 and H46 cells was analyzed by MTT method. The effect of galangin on Topo I activity was detected by the agarose gel electrophoresis method. Furthermore, the interaction between galangin and Topo I was evaluated by fluorescence spectroscopy. Finally, the eff ect of galangin on the Topo I structure was discussed.@*RESULTS@#Galangin could induce the apoptosis of A549 and H46 cells (IC50 was 0.221 mmol/L and 0.173 mmol/L, respectively). Agarose gel electrophoresis showed that galangin exerted significant inhibitory effect on Topo I activity. Fluorescence spectrum analysis showed that galangin was able to quench Topo I fluorescence, and hydrophobic interaction was the main driving force. Circular dichroism analysis showed that galangin induced Topo I conformation change and increased the content of α-helix, which prevented the formation of active center and in turn led to the decrease in Topo I activity. Molecular simulation results showed that galangin could bind to the active center of Topo I to form hydrogen bonds with the catalytic site at Arg364 and Asn352.@*CONCLUSION@#Galangin is able to inhibit Topo I activity and to reduce the unwinding rate of single stranded DNNA in tumor cells, which plays an important role in induction of A549 and H46 cell apoptosis.

Synthesis and structure-activity relationship of cycloberberine as anti-cancer agent / 药学学报

A series of cycloberberine derivatives were designed, synthesized and evaluated for their anti-cancer activities in vitro. Among these analogs, compounds 6c, 6e and 6g showed strong inhibition on human HepG2 cells. They afforded a potent effect against DOX-resistant MCF-7 breast cells as well. The primary mechanism showed that cell cycle was blocked at G2/M phase of HepG2 cells treated with 6g using flow cytometry assay. It significantly inhibited the activity of DNA Top I at the concentration of 0.1 mg mL-1. Our results provided a basis for the development of this kind of compounds as novel anti-cancer agents.

A Case of Typhlitis Developed after Chemotherapy with Irinotecan and Cisplatin in a Patient with Small Cell Lung Carcinoma / 결핵및호흡기질환

Typhlitis is a necrotizing colitis that usually occurs in neutropenic patients and develops most often in patients with hematologic malignancies such as leukemia and lymphoma. Typhlitis may proceed to bowel perforation, peritonitis and sepsis, which requires immediate treatment. Irinotecan is a semisynthetic analogue of the natural alkaloid camptothecin which prevents DNA from unwinding by inhibition of topoisomerase I. It is mainly used in colon cancer and small cell lung carcinoma (SCLC), of which the most common adverse effects are gastrointestinal toxicities. To the best of our knowledge, no case of typhlitis after chemotherapy with a standard dose of irinotecan in a solid tumor has been reported in the literature. We, herein, report the first case of typhlitis developed after chemotherapy combining irinotecan and cisplatin in a patient with SCLC.

Antibacterial activity and mechanism of baicalein / 药学学报

Baicalein (BAI) is an effective bactericide. The antibacterial activity and mechanism experiments were carried out by determining conductivity and content of macromolecules of membrane penetrability, the oxidative respiratory metabolism and protein synthesis changes and the inhibition of DNA topoisomerase activities. Electrical conductivity and the number of large molecules of BAI increased 2.48% and 1.8%, respectively, than that of the control. However, the membrane integrity did not destroyed by BAI directly. With BAI treatment, inhibition rates of activities for SDH and MDH were 56.2% and 57.4%, respectively, demonstrating that BAI could inhibit cell respiratory. After treated with BAI for 20 h, the total soluble content of proteins decreased by 42.83%. Moreover, the activities of DNA topoisomerase I and II were inhibited completely by 0.2 mmol x L(-1) BAI. These results indicated that BAI had obvious antibacterial activity on Staphylococcus aureus. The mechanism is that it could affect bacterial membrane penetrability, inhibit protein synthesis and influence SDH, MDH and DNA topoisomerase I and II activities to exert its antibacterial functions.

The synergistic antitumor effects of berberine alpha-hydroxy-beta-decanoylethyl sulfonate with hydroxycamptothecine and its effect on topoisomerase / 药学学报

Synergistic antitumor effects of HB (berberine alpha-hydroxy-beta-decanoylethyl sulfonate, houttuyn berberine) with HCPT (hydroxycamptothecine), and its correlative mechanism were studied in vitro. MTT assay was employed to determine the cytotoxicity of HB combined with HCPT in tumor cells culture in vitro, IC50 and combination index (CI value) were used to evaluate the synergistic effects. The supercoiled DNA relaxation mediated by topoisomerase I & II was measured by agarose gel electrophoresis assay, and influence of HB was detected. The results showed that HB could inhibit the proliferation of tumor cells (SGC-7901, SW1116 and SW480) in vitro, and the inhibition ratio was increased, IC50 was reduced when combining with HCPT. CI value of the two drugs was less than 1 in HepG2, SW480, SGC-7901 and SW1116 cells. The lowest value was 0.447, 0.626, 0.161 and 0.178 in these tumor cells, respectively, further indicating HB has synergistic action with HCPT on suppressing tumor proliferation. The agarose gel electrophoresis assay showed HB can inhibit topoisomerase I & II activity of SW480 cells at the concentration of 2.0-8.0 mg x L(-1). HCPT is a typical inhibitor of topoisomerase I , the synergistic action between HCPT and HB on suppressing tumor proliferation is perhaps related to the congenerous inhibition of topoisomerase.

Belotecan and Cisplatin Combination Chemotherapy for Previously Untreated Extensive-Disease Small Cell Lung Cancer

PURPOSE: Belotecan (Camtobell(R); Chong Keun Dang Co., Seoul, Korea) is a new camptothecin analog that inhibits topoisomerase I. We evaluated the efficacy and toxicity of belotecan combined with cisplatin in patients with previously untreated extensive-disease small cell lung cancer (ED-SCLC) and who were without evidence of brain metastases. MATERIALS AND METHODS: Twenty patients with previously untreated ED-SCLC were treated with belotecan (0.5 mg/m2/day) on days 1~4 and with cisplatin (60 mg/m2/day) on day 1 of a 3-week cycle. RESULTS: Of the 19 assessable patients, 16 had an objective tumor response, including two complete responses, for an overall response rate of 84.2%. Toxicity was evaluated in all 20 patients who received a total of 106 cycles (median cycles/patient, 5.5; range, 1~9). The major grade 3/4 hematologic toxicities were neutropenia (67.9% of cycles), anemia (19.8% of cycles) and thrombocytopenia (33.9% of cycles). No grade 3/4 non-hematologic toxicities were observed. No treatment-related deaths occurred. The median progression-free and overall survivals were 7.06 months (95% confidence interval [CI], 3.98~10.14 months) and 9.96 months (95% CI, 6.12~13.80 months), respectively. CONCLUSION: Combination chemotherapy with belotecan plus cisplatin is an effective treatment for ED-SCLC with acceptable hematologic and non-hematologic toxicities.

Anti-epidermal growth factor receptor (EGFR) monoclonal antibody and DNA topoisomerase inhibitor reduce growth of salivary adenoid cystic carcinoma in a murine model

INTRODUCTION: Epidermal growth factor receptor (EGFR) is expressed in human epithelial tumors including salivary cancers, and known to be correlated with tumor progression and poor clinical courses in some epithelial tumors. In this study, we determined the therapeutic effect of the anti-EGFR monoclonal antibody Erbitux (C225, cetuximab) in combination with the DNA topoisomerase I inhibitor irinotecan (CPT-11) on human salivary adenoid cystic carcinoma (SACC) cells growing in nude mice. MATERIALS AND METHODS: At first, immunocytochemical analysis for the expression of EGFR and phosphorylated EGFR (pEGFR) on a human salivary ACC cell line (ACC3). To determine the in vivo effects of Erbitux and CPT-11, nude mice with orthotopic parotid tumors were randomized to receive intraperitoneal Erbitux (1 mg) two times per week, intraperitoneal Irinotecan (50 mg/kg) once per week, Erbitux plus CPT-11, or placebo. (control) Tumor volume and weight were measured. And mechanisms of in vivo activity of Erbitux and/or CPT-11 were determined by immunohistochemical/immunofluorescent analyses. RESULTS: Immunocytochemical staining of ACC3 demonstrated that EGFR was expressed and phosphorylated. CPT-11 inhibited ACC tumor growth in nude mice. Tumors of mice treated with CPT-11 and CPT-11 plus Erbitux exhibited increased tumor cell apoptosis and decreased microvessel density, which correlated with a decrease in the tumor volume in nude mice. But, CPT-11 seems not to be synergistic with Erbitux in our ACC3 model system. CONCLUSION: These results suggest that anti-EGFR monoclonal antibody and the DNA topoisomerase I inhibitor will be effective in the treatment of recurred or metastatic lesions of salivary ACC.

Successful Treatment of Small-Cell Lung Cancer With Irinotecan in a Hemodialysis Patient With End-Stage Renal Disease

The prognosis of patients with end-stage renal disease has improved with advances in hemodialysis techniques. However, many patients who undergo hemodialysis suffer from various types of cancer. Limited data is available to guide clinical management of these patients who may have impaired renal function. Here, we report our experience with the use of irinotecan for the treatment of a hemodialysis patient with small-cell lung cancer and end-stage renal disease.

Biomarkers for Colorectal Cancer Treatment / 대한소화기학회지

Individualized tailored therapy is a currently pursuing direction for improving the outcome of patients with colorectal cancer. Targeted therapy is the potential strategy to reach this goal by evaluating status of the presumed targets and their related effector molecules and by maximizing the efficacy of chemotherapeutic agents with less toxicity in individual patient. Numerous hurdles should be overcome, however, because therapeutic outcome can be affected by multiple components; tumor characteristics such as somatic mutations at the DNA, RNA, and protein levels; patient characteristics like germline genetic polymorphisms in enzymes linked to drug metabolism; and environmental factors that include diet and physical activity. Currently, large numbers of potential biomarkers have been proposed but have not yet accomplished supporting evidences for their routine usage in clinics. Therefore, clinical trials driven by molecular targets and relevant biomarkers for the understanding of the conflicting data are needed to make markers available in clinical practice.

Effect of Lewis y antigen on regulating gene expression of partial drug resistance associated proteins in human ovarian cancer cell line RMG-I-H / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the influence of Lewis y antigen on the gene expression of partial drug resistance associated proteins in human ovarian cancer cell line RMG-I-H.</p><p><b>METHODS</b>RT-PCR was used to determine the gene expressions of partial drug resistance associated proteins in RMG-I-H cell line transfected with alpha1, 2-fucosyltransferases gene and RMG-I cell line, as well as in RMG-I-H treated with or without anti-Lewis y monoclonal antibody at the concentration of 10 micro/g/ml. The immunocytochemical method was used to detect the expression of P-glycoprotein (P-gp) in RMG-I and RMG-I-H cell lines. RMG-I and RMG-I-H cells were transplanted into nude mice and the expression of P-gp in the tissues was measured by immunohistochemistry.</p><p><b>RESULTS</b>The mRNA expressions of protein kinase C-alpha (PKC-alpha), topoismerase I ( Topo I ), multidrug resistance-associated protein-1 (MRP-1), and MRP-2 were significantly higher in RMG-I-H cells than those in RMG-I cells (0.46 +/- 0.02 vs. 0.27 +/- 0.05, 0.82 +/- 0.08 vs. 0.52 +/- 0.04, 0.66 +/- 0.07 vs. 0.34 +/- 0.12, and 0.44 +/- 0.08 vs. 0.23 +/- 0.05; all P < 0.05). However, the mRNA expression of multi-drug resistance 1 (MDR-1) was significantly lower in RMG-I-H cells than that in RMG-I cells (0.26 +/- 0.05 vs. 0.45 +/- 0.08, P < 0.05). The P-gp level increased in RMG-I-H cells compared with that in RMG-I cells both in vivo and in vitro (P < 0.05). Expressions of MDR-1, MRP-1, MRP-2, PKC-alpha, and Topo I mRNA decreased by the time in RMG-I-H cells treated with anti-Lewis y monoclonal antibody (all P < 0.05), while mRNA expressions of those genes in the control group did not statistically change (P > 0.05). In addition, MDR-1, MRP-1, MRP-2, PKC-alpha, and Topo I mRNA expressions were significantly lower in RMG-I-H cells treated with anti-Lewis y monoclonal antibody than those in the control group at 6 hours (all P < 0.05) and the inhibition ratios were 48.55%, 77.50%, 70.18%, 45.86%, and 46.13%, respectively.</p><p><b>CONCLUSION</b>The Lewis y antigen of the human ovarian cancer cell surface is closely correlated with the regulation on the gene expression of partial drug resistance associated proteins.</p>

Acute Respiratory Distress Syndrome after Topotecan Therapy in a Patient with Small Cell Lung Cancer / 결핵및호흡기질환

Small cell lung cancer is characterized by an aggressive clinical course and a high tendency for early dissemination in spite of a good chemotherapy response. Topotecan is a topoisomerase I inhibitor, and it is used as second-line treatment for small cell lung cancer. The reported dose-limiting adverse reactions to topotecan are mainly hematologic. Yet pulmonary toxicity associated with topotecan is known to be rare. We report here on a case that showed the development of acute respiratory distress syndrome during the 3rd cycle of topotecan chemotherapy in a patient with small cell lung cancer. He developed dyspnea and respiratory failure, and the chest CT scan revealed diffuse ground-glass opacity that was probably due to chemotherapy-related pulmonary toxicity. He finally died of acute respiratory distress syndrome.

The efficacy and toxicity of topotecan in combination with platinum in patients with recurrent epithelial ovarian cancer and primary peritoneal carcinomatosis / 대한산부인과학회지

OBJECTIVE: The aim of this study was to evaluate the efficacy and toxicity of topotecan, camptothecin analogue topoisomerase I inhibitor, as the combination therapy with platinum in patients with recurrent epithelial ovarian carcinoma and primary peritoneal carcinomatosis. METHOD: In this study, patients who were treated with topotecan between January 2000 and June 2007 at Asan Medical Center, Seoul, Korea were reviewed. Fifty-one patients with recurrent ovarian carcinoma and peritoneal carcinomatosis were included. These patients' data were analyzed by review of medical records and pathologic and laboratory reports retrospectively. Response was assessed by Response Evaluation Criteria in Solid Tumors (RECIST) criteria for patients with measurable disease and CA-125 response criteria for patients with non-measurable disease. The toxicities were evaluated according to NCI CTC (Common Toxicity Criteria) version 3.0. RESULTS: The mean age of patients was 53.4 years (ranged between 37 and 69). Forty-four patients had been evaluated by RECIST criteria. The overall response rate was 22.8% (10/44). Platinum-sensitive patients showed more favorable response rate (26.9%) than platinum-resistant patients (16.7%), however, it was not significant statistically (p=0.425). Platinum-sensitive group had significantly longer response duration (12.14 vs. 3.33 months, p=0.022) and time-to-progression (11.34 vs. 7.33 months, p=0.042) than platinum-resistant group. Heavily pretreated group, three or more prior regimens were used, had no significant differences from another group. The most common adverse effect of topotecan in combination with platinum was hematologic toxicity; grade 3/4 neutropenia was 30.6%, anemia was 42.7%, and thrombocytopenia was 8.37% in total 265 cycles of chemotherapy, however, it was tolerable. CONCLUSION: Topotecan in combination with platinum is considered as effective regimen with acceptable toxicity in treating recurrent epithelial ovarian carcinoma and primary peritoneal carcinomatosis who have failed previous treatment with platinum-containing chemotherapy.

Down-regulation of TopI by RNA interference reduces the drug-sensitivity of small cell lung cancer cell lines to topotecan / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the expressions of TopI gene in small cell lung cancer cell line H446, and explore the influence of TopI on the chemosensitivity of the cell line to topotecan (TPT).</p><p><b>METHODS</b>Western blot was performed to detect the TopI expression in H446 cells. Lipofectamine 2000 was used for the transient transfection of H446 cells by siRNA, and the transfection efficacy was detected. TopI mRNA was analyzed by quantitative RT-PCR and TopI protein was detected by Western blot to selected effective siRNA. The drug-sensitivity to topotecan (TPT) was evaluated by MTT assay.</p><p><b>RESULTS</b>TopI gene was expressed in H446 cells. Lipofectamine 2000 mediated the siRNA effectively (88.67%). Compared with its parental cells, RT-PCR results showed that TopI mRNAs in transfected cells were reduced by (95.7 +/- 1.6)%, (90.8 +/- 1.6)%, (96.1 +/- 2.7)% and (96.3 +/- 1.8)%, respectively, and decreased significantly at protein level. By MTT assay, the inhibition rate of TPT to H446 cells transfected by siRNA was lower than that of control group at same concentrations (P < 0.01).</p><p><b>CONCLUSION</b>siRNAs can silence the expression of TopI and decrease the drug-sensitivity of H446 cells to TPT.</p>

La ADN topoisomerasa tipo I de protozoos patógenos como Diana terapéutica de fármacos antitumorales / Type I DNA topoisomerase from protozoan pathogens as a potential target for anti-tumoral drugs

La utilización intensiva de fármacos antiparasitarios es la causa principal de la aparición de microorganismos parásitos multirresistentes en las regiones del planeta donde son precisamente endémicos. Los agentes etiológicos de las denominadas enfermedades tropicales -malaria, criptosporiodiosis, enfermedad del sueño, enfermedad de Chagas o los distintos tipos de leishmaniosis- son protozoos unicelulares sobre los que no se ha desarrollado en la actualidad ninguna vacuna eficaz y cuyo tratamiento se basa en medidas sanitarias preventivas y en el uso de medicamentos. La quimioterapia antiparasitaria actual es cara, no está ausente de efectos adversos y no supone beneficios a las empresas que la comercializan, por lo que la inversión en I & D es marginal comparada con la llevada a cabo para otros procesos patológicos de menor relevancia médica. La identificación de las ADN topoisomerasas como dianas farmacológicas se basa en los excelentes resultados obtenidos en los ensayos clínicos llevados a cabo con los derivados de la camptotecina en la terapia antitumoral. Las importantes diferencias estructurales entre las ADN topoisomerasas de tipo I de tripanosomas y leishmanias con respecto a sus homólogas de mamífero ha abierto un nuevo campo de investigación que combina las técnicas de biología molecular con la cristalización de proteínas para poder diseñar nuevos fármacos dirigidos específicamente a su inhibición. Revisamos aquí las características de estas nuevas dianas farmacológicas, así como los compuestos que en el momento están siendo utilizados para su inhibición en los agentes parasitarios que causan las principales enfermedades tropicales.

The intensive use of antiparasitic drugs is the main cause of the emergence of multiresistant parasite strains on those regions where these parasites are endemic. The aetiological agents of the so-called tropical diseases viz. malaria, cryptosporidiosis, sleeping sickness, Chagas disease or leishmaniasis, among others, are unicellular protozoan parasites with no immune-prophylactic treatment and where the chemotherapeutical treatment is still under controversy. At present, the chemotherapeutic approach to these diseases is expensive, has side or toxic effects and it does not provide economic profits to the Pharmaceuticals which then have no or scarce enthusiasm in R & D investments in this field. The identification of type I DNAtopoisomerases as promising drug targets is based on the excellent results obtained with camptothecin derivatives in anticancer therapy. The recent finding of significant structural differences between human type I DNAtopoisomerase and their counterparts in trypanosomatids has open a new field in drug discovery, the aim is to find structural insights to be targeted by new drugs. This review is an update of DNA-topoisomerases as potential chemotherapeutic targets against the most important protozoan agents of medical interest.

[In vitro cytotoxicity evaluation of sixteen new n-piperazinyl quinolone derivatives against a panel of tumor cell lines]

Fluoroquinolones are potent inhibitors of bacterial topoisomerase II. They can also inhibit eukaryotic topoisomerase, and may confer antitumoral properties. In this study the antitumoral activity of a new series of N-substituted piperazinyl- fluoroquinolones against a panel of human tumor cell lines was determined by MTT assays. Among the tested compounds N-[2- [5-bromo-2-thienyl]-2-oxoethyl] [C1,N1,E1], N-[2- [5-bromo-2-thienyl]-2-[hydroxyimino] ethyl][C2,N2,E2] and N-[2-[5-bromo-2-thienyl]-2-[phenylmethoxyimino] ethyl] [C3,N3,E3] piperazinyl quinolones exhibited the most cytotoxic activities [mean IC50s = 2.5 to 3 microg/ml], comparable to that of the Etoposide [mean IC50= 1.7micro g/ml]. Replacement of the 5- bromo-2-thienyl with 4- fluorophenyl or 2, 6- difluorophenyl rings leads to variable inhibition activity. The quinolone activity was enhanced by the presence of a chlorine and two fluorine atoms at the benzyl and phenyl groups, especially against ACHN renal adenocarcinoma cell line. These data suggest that these series of quinolones provide good models for the further design of potent antitumor compounds