MicroRNA profiling in human breast cancer cell lines exposed to the anti-neoplastic drug cediranib.

Cediranib, a pan-tyrosine kinase inhibitor is showing promising results for the treatment of several solid tumours. In breast cancer, its effects remain unclear, and there are no predictive biomarkers. Several studies have examined the expression profiles of microRNAs (miRNAs) in response to different chemotherapy treatments and found that the expression patterns may be associated with the treatment response. Therefore, our aim was to evaluate the cellular behaviour and differential expression profiles of miRNAs in breast cancer cell lines exposed to cediranib. The biological effect of this drug was measured by viability, migration, invasion and cell death in in vitro assays. Signaling pathways were assessed using a human phospho-receptor tyrosine kinase array. Furthermore, using a miRNA array and quantitative real-time PCR (qRT­PCR), we assessed the relative expression of miRNAs following cediranib treatment. The breast cancer cell lines exhibited a distinct cytotoxic response to cediranib treatment. Cediranib exposure resulted in a decrease in the cell migration and invasion of all the breast cancer cell lines. Treatment with cediranib appeared to be able to modulate the activation of several RTKs that are targets of cediranib such as EGFR and a new potential target ROR2. Furthermore, this drug was able to modulate the expression profile of different microRNAs such as miR-494, miR-923, miR-449a, miR-449b and miR-886-3 in breast cancer cell lines. These miRNAs are reported to regulate genes involved in important molecular processes, according to bioinformatics prediction tools.

A calcineurin inhibitory protein overexpressed in Down's syndrome interacts with the product of a ubiquitously expressed transcript.

The Down's syndrome candidate region 1 (DSCR1) protein, encoded by a gene located in the human chromosome 21, interacts with calcineurin and is overexpressed in Down's syndrome patients. As an approach to clarifying a putative function for this protein, in the present study we used the yeast two-hybrid system to identify DSCR1 partners. The two-hybrid system is a method that allows the identification of protein-protein interactions through reconstitution of the activity of the yeast GAL 4 transcriptional activator. The gene DSCR1 fused to the GAL 4 binding domain (BD) was used to screen a human fetal brain cDNA library cloned in fusion with the GAL 4 activation domain (AD). Three positive clones were found and sequence analysis revealed that all the plasmids coded for the ubiquitously expressed transcript (UXT). UXT, which is encoded in human Xp11, is a 157-amino acid protein present in both cytosol and nucleus of the cells. This positive interaction of DSCR1 and UXT was confirmed in vivo by mating the yeast strain AH109 (MATa) expressing AD-UXT with the strain Y187 (MATalpha) expressing BD-DSCR1, and in vitro by co-immunoprecipitation experiments. These results may help elucidate a new function for DSCR1 and its participation in Down's syndrome pathogenesis.

A calcineurin inhibitory protein overexpressed in Down's syndrome interacts with the product of a ubiquitously expressed transcript

The Down's syndrome candidate region 1 (DSCR1) protein, encoded by a gene located in the human chromosome 21, interacts with calcineurin and is overexpressed in Down's syndrome patients. As an approach to clarifying a putative function for this protein, in the present study we used the yeast two-hybrid system to identify DSCR1 partners. The two-hybrid system is a method that allows the identification of protein-protein interactions through reconstitution of the activity of the yeast GAL 4 transcriptional activator. The gene DSCR1 fused to the GAL 4 binding domain (BD) was used to screen a human fetal brain cDNA library cloned in fusion with the GAL 4 activation domain (AD). Three positive clones were found and sequence analysis revealed that all the plasmids coded for the ubiquitously expressed transcript (UXT). UXT, which is encoded in human Xp11, is a 157-amino acid protein present in both cytosol and nucleus of the cells. This positive interaction of DSCR1 and UXT was confirmed in vivo by mating the yeast strain AH109 (MATa)expressing AD-UXT with the strain Y187 (MATalfa) expressing BD-DSCR1, and in vitro by co-immunoprecipitation experiments. These results may help elucidate a new function for DSCR1 and its participation in Down's syndrome pathogenesis.