ID	Duplex structure	Position	Score	MFE
1	miRNA 3' ucuugucauaAAGGUCCUUAgg 5' |||:|||||| Target 5' gtgcctgcccTTCTAGGAATgg 3'	5 - 26	136.00	-9.40
2	miRNA 3' ucuugucauaaaggUCCUUAGg 5' ||||||: Target 5' tcattcactaaggaAGGAATTg 3'	99 - 120	124.00	-5.20
3	miRNA 3' ucuuGUCAUAAAGGUCCUUAgg 5' ||| :|||:::||| | Target 5' gtgcCAGGGTTTTTGGGATTaa 3'	72 - 93	102.00	-9.20

ID	Duplex structure	Position
1	miRNA 3' ucCCUAAGGACCCUUUUGACCug 5' ||| | :||||: |||||| Target 5' ggGGAGU-UUGGGGCAACUGGuu 3'	2 - 23

- Cell, 2009

MicroRNAs (miRNAs) are posttranscriptional modulators of gene expression and play an important role in many developmental processes. We report here that expression of microRNA-145 (miR-145) is low in self-renewing human embryonic stem cells (hESCs) but highly upregulated during differentiation. We identify the pluripotency factors OCT4, SOX2, and KLF4 as direct targets of miR-145 and show that endogenous miR-145 represses the 3' untranslated regions of OCT4, SOX2, and KLF4. Increased miR-145 expression inhibits hESC self-renewal, represses expression of pluripotency genes, and induces lineage-restricted differentiation. Loss of miR-145 impairs differentiation and elevates OCT4, SOX2, and KLF4. Furthermore, we find that the miR-145 promoter is bound and repressed by OCT4 in hESCs. This work reveals a direct link between the core reprogramming factors and miR-145 and uncovers a double-negative feedback loop involving OCT4, SOX2, KLF4, and miR-145.

- J Dermatol, 2012

Previously, we showed that transient transfection with OCT4 not only produced high expression of Oct4 in skin keratinocytes, but also caused a generalized demethylation of keratinocyte DNA. We hypothesized that DNA demethylation alone might allow expression of endogenous OCT4. Here, we report that treatment with the cancer drug decitabine results in generalized DNA demethylation in skin keratinocytes, and by 48 h after treatment, 96% of keratinocytes show expression of the endogenous Oct4 protein and the OCT4 repressor mir-145. This is true for keratinocytes only, as skin fibroblasts treated similarly show no OCT4 or mir-145 expression. Decitabine-treated keratinocytes also show increased mir-302c and proliferation similar to other Oct4(+) cells. Treatment with doxorubicin, another cancer drug, induces expression of mir-145 only in cells that already express OCT4, suggesting that Oct4 regulates its own repressor. Co-treatment with decitabine and doxorubicin results first in increased OCT4 and mir-145, then a decrease in both, suggesting that OCT4 and mir-145 regulate each other. The novel strategy presented here provides a regulatable system to produce Oct4(+) cells for transformation studies and provides a unique method to study the effects of endogenous Oct4 in cancer cells and the surrounding somatic cells.