Reductions in the expression of miR-124-3p, miR-128-1, and miR-221-3p in pediatric astrocytomas are related to high-grade supratentorial, and recurrent tumors in Mexican children.
OBJECTIVE
Astrocytomas are the most frequent type of tumor of the central nervous system in children. Hence, it is important to describe markers that may improve our understanding of their behavior. Mature microRNAs (miRNAs) may be such biological markers. They are small molecules of RNA that regulate gene expression post-transcriptionally. Due to their importance in cancer, the objective of the present study was to determine the profile of expression of precursor and mature forms of miR-124-3p, miR-128-1, and miR-221-3p using RT-qPCR in pediatric samples.


METHODS
A total of 57 astrocytomas embedded in paraffin were selected. As controls, the study included 13 samples of normal brain tissue.


RESULTS
Three of eight miRNAs were selected after a preliminary screening. All the miRNAs showed higher levels of expression in normal brain tissue. The expression of miR-124-3p and miR-128-1 decreased in astrocytomas than in normal brain tissue in all grades (p < 0.05 in both cases), and this reduction was most evident in GIV (407- and 1,469-fold, respectively); however, the expression of the precursor forms pre-miR-128-1 and pre-miR-221 was higher in GIV (3.5-fold) than in GI. The levels of miR-128-1 were higher in infratentorial tumors than in supratentorial cases (p = 0.006). Finally, the expression of miR-221-3p was higher in non-recurrent tumors and live patients (p = 0.0185 and p = 0.0004, respectively).


CONCLUSIONS
The low expression of these miRNAs may constitute a potential marker of astrocytomas that correlates with localization, possibly due to alterations in the maturation processes of these miRNAs that produced low mature forms in patients with recurrent pediatric astrocytomas.
Laboratory of Molecular Biology, Department of Pathology, Hospital Infantil de México Federico Gómez, Dr. Márquez 162, Col. Doctores, 06720, Del. Cuauhtémoc, D.F., Mexico.
Pilar
P
Eguía-Aguilar
Mario
M
Pérezpeña-Díazconti
Eduardo
E
Benadón-Darszon
Fernando
F
Chico-Ponce de León
Luis
L
Gordillo-Domínguez
Samuel
S
Torres-García
Stanislaw
S
Sadowinski-Pine
Francisco
F
Arenas-Huertero
D001254:Astrocytoma / Q000235:genetics / Q000473:pathology*; D014408:Biomarkers, Tumor / Q000235:genetics; D001932:Brain Neoplasms / Q000235:genetics* / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D007223:Infant; D008297:Male; D008800:Mexico; D035683:MicroRNAs / Q000096:biosynthesis*; D060787:Neoplasm Grading; D009364:Neoplasm Recurrence, Local / Q000235:genetics / Q000473:pathology; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction
D014408:Biomarkers, Tumor; D035683:MicroRNAs; C509207:MIRN124 microRNA, human; C545189:MIRN128 microRNA, human; C525709:MIR221, human