Protective role of humic acids against picloram-induced genomic instability and DNA methylation in Phaseolus vulgaris

AbstractOncogene-evoked replication stress (RS) fuels genomic instability in diverse cancer types. Here we report that BRCA1, traditionally regarded a tumour suppressor, plays an unexpected tumour-promoting role in glioblastoma (GBM), safeguarding a protective response to supraphysiological RS levels. Higher BRCA1 positivity is associated with shorter survival of glioma patients and the abrogation of BRCA1 function in GBM enhances RS, DNA damage (DD) accumulation and impairs tumour growth. Mechanistically, we identify a novel role of BRCA1 as a transcriptional co-activator ofRRM2(catalytic subunit of ribonucleotide reductase), whereby BRCA1-mediated RRM2 expression protects GBM cells from endogenous RS, DD and apoptosis. Notably, we show that treatment with a RRM2 inhibitor triapine reproduces the BRCA1-depletion GBM-repressive phenotypes and sensitizes GBM cells to PARP inhibition. We propose that GBM cells are addicted to the RS-protective role of the BRCA1-RRM2 axis, targeting of which may represent a novel paradigm for therapeutic intervention in GBM.

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DEHYDRINS PATTERNS IN COMMON BEAN EXPOSED TO DROUGHT AND WATERED CONDITIONS

Revista Fitotecnia Mexicana ◽

10.35196/rfm.2014.1.59 ◽

2014 ◽

Vol 37 (1) ◽

pp. 59

Author(s):

M. Claudia Castañeda-Saucedo ◽

Leobigildo Córdova-Téllez ◽

Ernesto Tapia-Campos ◽

Adriana Delgado-Alvarado ◽

Víctor A. González-Hernández ◽

...

Keyword(s):

Drought Stress ◽

Phaseolus Vulgaris ◽

Common Bean ◽

Transient Response ◽

Consensus Sequence ◽

Protective Role ◽

Phaseolus Vulgaris L ◽

Major Constraint ◽

Induced Proteins

Drought is a major constraint for common bean (Phaseolus vulgaris L.) production in México. Dehydrins are constitutive or stress-induced proteins related with a protective role of membranes and macromolecules against denaturation, thus preventing loss of their function. In this work, seed production and patterns of dehydrins accumulation in leaves and pods were evaluated in common bean cv. ‘Otomí’ subjected to drought, as compared with well-irrigated plants. Drought applied at pod formation and seed filling (SF) reduced yield up to 57 %. An antibody against a consensus sequence present in most dehydrins allowed for dehydrin identification. Two dehydrins of 82 and 73 kDA turned up both in leaves and pods throughout all the evaluated conditions. Presumably, both dehydrins are constitutive in the ‘Otomí’ cultivar. These dehydrins showed higher expression than controls in leaves after 6 d of drought at seedling and SF stages, and in pods 6 d after drought had started at SF. Increased expression might provide better protection during early stages of seedling and seed development. Increments on 63, 36 and 22 kDa dehydrin expression in pods at late SF might coincide with plant developmental programs, which prepare seed for desiccation. Dehydrins of 158, 54, 46, and 41 kDa were detected in pods 10 d after floral opening as a transient response to drought stress in SF. These results indicate dehydrins are relevant during plant development, as well as during drought stress.

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