Expression of Cytochrome P450 Enzymes in Pediatric Non-Rhabdomyosarcoma Soft Tissue Sarcomas: Possible Role in Carcinogenesis and Treatment Response.

The 5-year relative survival rate estimate of treated patients with non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) is ∼50% since they generally present with tumor progression, relapse, metastasis, and/or chemoresistance. The expression of cytochrome P450 (CYP) enzymes in malignancies can affect the pharmacology of drugs commonly used in chemotherapy or confer susceptibility to development of chemical carcinogenesis; in addition, their specific tumor expression can be used as a therapeutic target. Using qPCR and Western blot assays, the expression of CYP1B1, CYP2E1, CYP3A4, and CYP3A5 were analyzed in a cohort of tumor tissue paired with non-malignant adjacent tissue of patients with NRSTS. The mRNA and protein expression of CYP1B1, CYP2E1, and CYP3A4 were significantly increased in tumor tissue. We propose that the expression of these isoforms is related to carcinogenesis and chemoresistance frequently observed in these neoplasms.

MDR1 not CYP3A4 gene expression is the predominant mechanism of innate drug resistance in pediatric soft tissue sarcoma patients.

BACKGROUND: Intratumoral up-regulation of genes coding for drug transporters and metabolizing enzymes, such as MDR1 and CYP3A4, after chemotherapy are linked to cancer drug resistance. However their expression in primary soft tissue sarcomas (STS) prior to drug treatment and their role in innate resistance remain unclear. OBJECTIVE: The aim of this study was characterize MDR1 and CYP3A4 expression pattern before to chemotherapy and its clinical implication in pediatric STS. METHODS: In this prospective study we analyzed MDR1 and CYP3A4 mRNA expression in both normal and tumor tissues from 28 newly diagnosed STS pediatric and then compared with patients' clinical-pathological data, including chemotherapy response. RESULTS: Our data showed that the expression of the MDR1 gene was significantly higher in malignant tissue than in the normal tissues of patients with STS. In addition, high MDR1 expression was significantly associated with local advances, as well as poor response to treatment. In contrast, CYP3A4 expression level was negligible in both tumoral and non-tumoral tissues. CONCLUSIONS: These results suggest that a significant mRNA level of MDR1 gene was intrinsically present in STS before exposure to chemotherapeutic drugs, suggesting that MDR1 may be important contributors of innate chemoresistance of this tumor type.

Social cognitive predictors of academic and life satisfaction: Measurement and structural equivalence across three racial/ethnic groups.

Data of 306 Caucasian American, 284 Asian American, and 259 Latino/a American college students were analyzed in this study to test a modified version of Lent and Brown's (2006, 2008) satisfaction model in the academic context. In addition to the full set of variables hypothesized in the original model, the modified academic satisfaction model also included independent and interdependent self-construals to represent one's cultural orientations. Comparisons between the hypothesized model and 2 alternative models showed that direct paths from extraversion and emotional stability added significantly to the predictions of academic satisfaction and life satisfaction for all 3 racial/ethnic groups while those from independent and interdependent self-construals also had the same effects for Latino/a American students. The hypothesized model offered excellent fit to the data of all 3 racial/ethnic groups. Consistent with theoretical prediction, academic supports, self-efficacy, outcome expectations, or goal progress formed pathways that mediated the relations of personality traits and self-construals to academic satisfaction or life satisfaction across 3 groups. Although full measurement equivalence (configural invariance and metric invariance) was observed, 4 structural paths and 16 indirect effects differed significantly by race/ethnicity. Most of these differences in structural paths and indirect effects occurred between Caucasian Americans and Asian Americans. On balance, findings of the study provided evidence for the cross-racial/ethnic validity of the modified academic satisfaction model while identifying racial/ethnic differences that might have useful clinical implications. (PsycINFO Database Record

Aspartame Administration and Insulin Treatment Altered Brain Levels of CYP2E1 and CYP3A2 in Streptozotocin-Induced Diabetic Rats.

This study demonstrates that aspartame consumption and insulin treatment in a juvenile diabetic rat model leads to increase in cytochrome P450 (CYP) 2E1 and CYP3A2 isozymes in brain. Diabetes mellitus was induced in postweaned 21-day-old Wistar male rat by streptozotocin. Animals were randomly assigned to one of the following groups: untreated control, diabetic (D), D-insulin, D-aspartame, or the D-insulin + aspartame-treated group. Brain and liver tissue samples were used to analyze the activity of CYP2E1 and CYP3A2 and protein levels. Our results indicate that combined treatment with insulin and aspartame in juvenile diabetic rats significantly induced CYP2E1 in the cerebrum and cerebellum without modifying it in the liver, while CYP3A2 protein activity increased both in the brain and in the liver. The induction of CYP2E1 in the brain could have important in situ toxicological effects, given that this CYP isoform is capable of bioactivating various toxic substances. Additionally, CYP3A2 induction in the liver and brain could be considered a decisive factor in the variation of drug response and toxicity.

Differential expression of cytochrome P450 enzymes in normal and tumor tissues from childhood rhabdomyosarcoma.

Intratumoral expression of genes encoding Cytochrome P450 enzymes (CYP) might play a critical role not only in cancer development but also in the metabolism of anticancer drugs. The purpose of this study was to compare the mRNA expression patterns of seven representative CYPs in paired tumor and normal tissue of child patients with rabdomyosarcoma (RMS). Using real time quantitative RT-PCR, the gene expression pattern of CYP1A1, CYP1A2, CYP1B1, CYP2E1, CYP2W1, CYP3A4, and CYP3A5 were analyzed in tumor and adjacent non-tumor tissues from 13 child RMS patients. Protein concentration of CYPs was determined using Western blot. The expression levels were tested for correlation with the clinical and pathological data of the patients. Our data showed that the expression levels of CYP1A1 and CYP1A2 were negligible. Elevated expression of CYP1B1 mRNA and protein was detected in most RMS tumors and adjacent normal tissues. Most cancerous samples exhibit higher levels of both CYP3A4 and CYP3A5 compared with normal tissue samples. Expression of CYP2E1 mRNA was found to be significantly higher in tumor tissue, however no relation was found with protein levels. CYP2W1 mRNA and/or protein are mainly expressed in tumors. In conclusion, we defined the CYP gene expression profile in tumor and paired normal tissue of child patients with RMS. The overexpression of CYP2W1, CYP3A4 and CYP3A5 in tumor tissues suggests that they may be involved in RMS chemoresistance; furthermore, they may be exploited for the localized activation of anticancer prodrugs.

Effect of mosquito mats (pyrethroid-based) vapor inhalation on rat brain cytochrome P450s.

The effect of transfluthrin (TF) or D-allethrin (DA) pyrethroid (PYR) vapors, often contained as main ingredients in two commercially available mosquito repellent mats, on cytochrome P450 (CYP) enzymes of rat brain and liver was assessed. Immunodetection of CYP2E1 and CYP3A2 proteins revealed their induction in cerebrum and cerebellum, but not in liver microsomes of rats exposed by inhalation to TF or DA. This overexpression of proteins correlated with an increase of their catalytic activities. The specifically increased expression of CYP isoenzymes, due to PYR exposure in the rat brain, could perturb the normal metabolism of endogenous and xenobiotic compounds and leads to increased risks of neurotoxicity by bioactivation, lipid peroxidation and DNA damage.

Tissue-specific induction of the carcinogen-inducible cytochrome P450 isoforms in the gastrointestinal tract.

Gastrointestinal tissues are directly exposed to dietary xenobiotics. In spite of this, modulation of cytochrome P450 (CYP) enzymes in the gastrointestinal tract is not well established. CYP induction could facilitate transformation of chemical agents to potentially toxic or carcinogenic metabolites. This might also determine drug efficacy, burden of foreign chemicals on tissues or bioavailability of certain therapeutic agents. In order to assess the induction of the CYP subfamilies 1A1/2, 2B1/2, 2E1 and 3A2 in the gastrointestinal tract, male Wistar rats were treated with phenobarbital/ß-naphthoflavone (PB/NF), cyclohexanol/albendazole (CH/ABZ) or toluene (TL). Microsomal fractions were prepared from tissue samples of the esophagus, the stomach, the duodenum, the colon and the liver. Western blot and enzymatic activity analyses revealed an increase in the expression and activity of CYP1A1/2 and CYP3A2 isoenzymes in the esophageal, duodenal and colonic microsomes from animals treated with PB/NF. CYP1A1/2 and CYP3A2 were induced in hepatic and duodenum microsomes by treatment with CH/ABZ. Our results demonstrate differential induction of CYP along the gastrointestinal tract by known CYP hepatic inducers, being the treatment with PB/NF the best induction system of the CYPs.

Comparación de dos tipos de trasplante experimental en el tratamiento del instestino corto letal / Comparison of two types of experimental transplant in the treatment of lethal shortgut syndrome

Objetivo. Evaluar la respuesta funcional, morbilidad y posibles cambios histoestructurales en animales enterectomizados y sin ciego, sujetos a dos tipos de trasplante anteral singénico. Material y método. Ensayo terapéutico-quirúrgico, aleatorio, controlado. Cuatro grupos de ratas Lewis macho de 8-10 semanas de vida se sometieron a los siguientes tratamientos: 1. Resección enteral letal (n=10). 2. Resección enteral letal + trasplante yeyuno-ileal total (n=28). 3. Resección enteral letal + trasplante segmentario distal de 40 por ciento y ciego (n=32). 4. Grupo testigo (n=10). Resultados. El 11 por ciento de los animales trasplantados falleció por fallas quirúrgicas. Hubo una proporción similar de complicaciones tardías en ambos grupos trasplantados: la más común fue obstrucción enteral; 20 por ciento de los trasplantes yeyuno-ileales presentó diarrea persistente. En los dos grupos trasplantados no se detectaron diferencias significativas, de sobrevida, incremento de peso, niveles séricos de proteínas, triglicéridos y prueba de absorción de la maltosa. En ambos tipos de injertos se observó hipertrofia de vellosidades y criptas. El injerto enteral se acompaño de cambios estructurales semejantes a los que se presentan en los remanentes inestinales en condiciones de déficit enteral postresección. Conclusión. El trasplante segmentario distal de intestino, con válvula íleaca y ciega, puede ser una buena opción terapéutica en la insuficiencia enteral irreversible, dado que la respuesta funcional y la morbilidad asociada no difieren de las del trasplante total

Cambios histoquímicos en la mucosa gástrica de ratas por el consumo de dietas hipersódicas durante el desarrollo / Histochemical changes in rats' gastric mucosa induced by the intake of high salt diets during postnatal development

La barrera de la mucosa gástrica es el principal mecanismo de protección para el estómago; sin embargo, existen elementos dietéticos irritantes consumidos a diario que pueden llegar a dañar dicha barrera, tal es el caso del cloruro de sodio o sal común. El presente estudio muestra que el consumo crónico de dietas hipersódicas durante el desarrollo posnatal de la rata Wistar, altera el tipo y distribución de mucopolisacáridos de la mucosa gástrica, presentando mucinas predominantemente de tipo intestinal (ácida), este cambio se puede considerar como una variable importante para el diagnóstico de diversas alteraciones gástricas

Efectos del destete precoz y tardío sobre el desarrollo del intestino delgado de la rata: un estudio morfométrico a nivel de microscopía optica / The effect of early and late weaning on the small bowel development in rats. A morphometric study with optical microscopy

El intestino delgado de la rata presenta cambios morfológicos y enzimáticos asociados con el destete, los cuales pueden ser alterados por el destete temprano. Sin embargo, el criterio morfométrico no ha sido considerado. Material y Métodos: En este estudio, los efectos del destete precoz (15 días) y prolongado (32 días) sobre el tamaño y número de vellosidades y criptas del intestino delgado, fueron analizados en ratas de 16 a 70 días de edad. Resultados: El destete precoz provocó un incremento temprano en el tamaño de las vellosidades, profundidad y número de criptas en el duodeno y yeyuno, mientras que el número de vellosidades disminuyó. Las crías amamantadas hasta los 32 días no mostraron alteraciones en los parámetros analizados. No obstante, el ileon no presento alteraciones con el destete precoz o prolongado. Conclusiones: Estos datos sostienen el concepto de un programa biológico intrínseco como control de dieta parece tener una función modificadora en el duodeno y el yeyuno

Lavado vascular y naloxona en la prevención de daño pulmonar ocasionado por isquemia distal / Vascular washing and naloxone in the prevention of lung damage caused by distal ischemia

El modelo en ratas de isquemia por bloqueo circulatorio de torso y patas traseras, cuando se prolonga 90 minutos o más, ocasiona infiltración alveolar de polimorfonucleares y macrófagos. El lavado vascular de la zona isquémica previo a la reperfusión, y el uso de naloxona disminuyen el grado de infiltración de los alvéolos pulmonares por polimorfonucleares activados. El estudio confirma el daño pulmonar por infiltrados leucocitarios activados por radicales libres de oxígeno en zonas isquémicas y después de su reperfusión en ratas