Glucocorticoid-dependent expression of IAP participates in the protection against TNF-mediated cytotoxicity in MCF7 cells.

BACKGROUND: Glucocorticoid receptor (GR) activation has been associated with breast cancer cell survival in vitro. Glucocorticoid (GC)-dependent protection against tumor necrosis factor (TNF)-induced cell death has been well characterized in MCF7 luminal A breast cancer cells. The GR activates a variety of protective mechanisms, such as inhibitors of apoptosis proteins (IAPs). However, the relative contribution of the GR-dependent expression of IAPs in the protection of cell death has not, to our knowledge, been evaluated. METHODS: MCF7 cells were used for all experiments. GR was activated with cortisol (CORT) or dexamethasone (DEX) and inhibited with mifepristone (RU486). Cell viability was determined in real-time with the xCELLigence™ RTCA System and at specific endpoints using crystal violet stain. The mRNA levels of the eight members of the IAP family were measured by qRT-PCR. The protein levels of GR, PR, ERα, HER2, PARP1, c-IAP1 and XIAP were evaluated by Western blot analysis. The knockdown of c-IAP1 and XIAP was accomplished via transient transfection with specific siRNAs. GR activation was verified by a gene reporter assay. Via the cBioportal interphase we queried the mRNA levels of GR and IAPs in breast cancer tumors. RESULTS: RU486 significantly inhibited the anti-cytotoxic effect of both GCs. PARP1 processing was diminished in the presence of both GCs. The combined treatments of GCs + TNF increased the relative mRNA levels of Survivin>c-IAP1 > NAIP>Apollon>XIAP>Ts-IAP > ML-IAP > c-IAP2. Additionally, GR mRNA content increased with the combined treatments of GCs + TNF. Sustained levels of the proteins c-IAP1 and XIAP were observed after 48 h of the combined treatments with GCs + TNF. With c-IAP1 and XIAP gene silencing, the GC-mediated protection was diminished. In the breast tumor samples, the GR mRNA was coexpressed with Apollon and XIAP with a Pearson coefficient greater than 0.3. CONCLUSIONS: The effect of GCs against TNF-mediated cytotoxicity involves increased mRNA expression and sustained protein levels of c-IAP1 and XIAP. The antagonist effects of RU486 and the qRT-PCR results also suggest the role of the GR in this process. This finding may have clinical implications because the GR and IAPs are expressed in breast tumor samples.

miR-34a in serum is involved in mild-to-moderate COPD in women exposed to biomass smoke.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is characterized by persistent respiratory symptoms and airflow limitation that is due to airway and/or alveolar abnormalities. The main causes of COPD are Gene-environment interactions associated with tobacco smoking (COPD-TS) and biomass smoke (COPD-BS). It is well know that microRNAs (miRNAs) participate in the control of post-transcriptional regulation and are involved in COPD-TS; nevertheless, those miRNAS are participating in the COPD-BS are unidentified. Thus, we studied which miRNAs are involved in COPD-BS (GOLD stages I-II). METHODS: In the screening phase, the profile of the miRNAs was analyzed in serum samples (n = 3) by means of a PCR array. Subsequently, the miRNAs were validated with RT-qPCR (n = 25) in the corresponding study groups. Additionally, the serum concentration of Notch1 was measured comparing COPD-BS vs COPD-TS. RESULTS: miR-34a was down-regulated in COPD- BS vs COPD-TS. In the other study groups, three miRNAs were differentially expressed: miR-374a was down-regulated in COPD-BS vs C, miR-191-5p was up-regulated in COPD-BS vs H-BS, and miR-21-5p was down-regulated in COPD-TS compared to the C group. Moreover, the serum concentration of Notch1, one of the targets of miR-34a, was increased in COPD-BS compared to women with COPD-TS. CONCLUSIONS: This is the first study in patients with COPD due to biomass that demonstrates miRNA expression differences between patients. The observations support the concept that COPD by biomass has a different phenotype than COPD due to tobacco smoking, which could have important implications for the treatment of these diseases.

Efecto de la prednisona, la azatioprina y la ciclosporina A sobre la cicatrización bronquial / Effects of prednisone, azathioprine and ciclosporine A on bronchial healing

El trasplante pulmonar es la única posibilidad terapéutica para los pacientes con pulmón en estado terminal; sin embargo, las complicaciones que se presentan después del transplante como la cicatrización bronquial deficiente, no han permitido que esta medida terapéutica sea muy exitosa. Esta complicación puede ser el resultado de varios factores como la inmunosupresión, la isquemia, las infecciones y/o el fenómeno de rechazo. En este trabajo se estudió el efecto de tres inmunosupresores (prednisona, azatioprina y ciclosporina A) en la cicatrización bronquial, en un modelo de autotransplante pulmonar canino. Se usaron tres parámetros comparativos para evaluar el efecto de los inmunosupresores sobre la anastomosis bronquial: el histológico (evaluación subjetiva de la cantidad de colágena que aparece en la anastomosis), la cuantificación de la concentración de la colágena por el método de Woessner y la medición de la fuerza tensil de ruptura (FTR). El grupo de prednisona a dosis alta mostró índice histológico de la colágena significativamente menor con respecto de los demás grupos. De la misma forma, la FTR fue también significativamente menor en el grupo de prednisona a dosis alta. La concentración de la colágena depositada no presentó diferencia entre ninguno de los grupos. Se concluye que las dosis altas de prednisona (4 mg/kg/día), afectan la anastomosis bronquial, pues disminuyen significativamente la FTR y el índice histológico de la colágena que se observó; sin embargo, este efecto no se debió a la cantidad de la colágena depositada, sino probablemente a la forma de depositarse de ésta o a una polimerización deficiente