Cell experiment:

The Oct4-luc or Nanog-luc cells are treated with compound OAC1 or its structural analogs OAC2, OAC3 at 1 μM concentration or at indicated concentrations. Other compounds used include 2 μM BIO, 2 μM BIX, 2 μM 5'-azacytidine, 25 μg/mL Vitamin C, 10 nM Am580, 5 μM tranylcypromine, and 0.5 mM valporic acid. Luciferase reporter assays are performed 24 h after compound treatment or at indicated time points. For Topflash reporter assays, 0.2 μg β-catenin–responsive Topflash reporter gene plasmid is introduced into CV1 cells using trasfection. Compounds are added 6 h after transfection. Luciferase activity is measured 48 h after compound treatment using the Glo Luciferase Assay System[2].

OAC2 is identified as an activator of octamer-binding transcription factor 4.

Octamer-binding transcription factor 4 (Oct4) has been found to be a key regulator of embryonic stem cell (ESC) pluripotency and cirtical to the reprogramming process.

In vitro: OAC2 was found to be able to activate both Oct4 and Nanog reporters to a similar extent as OAC1, which was the OAC analog showing greatest activating effects on both Oct4 and Nanog promoter-driven luciferase reporter genes. Moreover, in order to examine the developmental potential of 4F+OAC1- and 4F+OAC2-iPSCs, the authors differentiated such cells in vitro by using a standard embryoid body differentiation method. The immunostaining results showed that both the 4F+ OAC1-iPSCs and 4F+OAC2-iPSCs were able to effectively differentiate into characteristic smooth muscle actin (SMA)+ mesodermal cells, FoxA2+ endoderm cells, and Tuj1+ ectoderm cells as well [1].

In vivo: In animal to test the in vivo pluripotency of the 4F+ OAC2-induced iPSCs, the 4F+OAC2-iPSCs were transplanted the into immunodeficient Nude mice. Four to 6 weeks after transplantation, the 4F+OAC2-iPSCs could generate typical teratomas containing derivative of all three germ layers effectively, such as blood of mesoderm, intestinal epithelia of endoderm, as well as epidermis of ectoderm [1].

Clinical trial: Up to now, OAC2 is still in the preclinical development stage.

Reference:
[1] Li W,Tian E,Chen ZX,Sun G,Ye P,Yang S,Lu D,Xie J,Ho TV,Tsark WM,Wang C,Horne DA,Riggs AD,Yip ML,Shi Y.  Identification of Oct4-activating compounds that enhance reprogramming efficiency. Proc Natl Acad Sci U S A.2012 Dec 18;109(51):20853-8.