| Summary: | Acute myeloid leukemia (AML) is the most common acute leukemia in adults
and is characterized by immature myeloid cell proliferation which caused by bone
marrow failure. Studies shown prolonged SKP2 knockdown suppress telomerase
reverse transcriptase (TERT) expression in t(8;21) AML cells. Nevertheless, the
molecular mechanism of TERT regulation by SKP2 remain unclear. Therefore, the
aim of this study was to investigate the TERT mechanism by SKP2 in AML. In this
study, TERT expression reduced at gene and protein level after SKP2 suppression in
non t(8;21) AML cells. Accordingly, telomerase activity was also reduced in non
t(8;21) AML cells.Much research has been done on c-Myc and FOXO3 function in
cell cycle progression and TERT regulation. Result obtained show that c-Myc and
FOXO3 did not play a direct role in SKP2 mediated TERT regulation in t(8;21) and
non-t(8;21) AML cells at gene level. However, different pattern in c-Myc protein
expression was observed in non t(8;21) AML cells. Another observation were made in
t(8;21) AML cells after AML1/ETO knockdown where c-Myc was up-regulated at
gene and protein level. Due to increase in c-Myc expression levels, chromatin
immunoprecipitation (ChIP) was carried out and increased observed binding of c-Myc
to the TERT promoter was observed after AML1/ETO down-regulation. However, c
Myc binding to the TERT promoter failed to induce TERT transcription in t(8;21)
AML cells.Other proteins related to TERT mechanism observed were Rb, E2F1 and CDKN1B. Hypophosphorylation of Rb was observed up-regulated in non t(8;21)
AML cells after SKP2 knockdown yet no significant difference in E2F1 protein
expression was observed. Accumulation of CDKN1B was markedly related with
suppression of SKP2 in this studies.
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