PB28

PB28 is a potent, high affinity (Ki = 0.34 nM1) σ2 agonist (1). Its antiproliferative (EC50 ~ 0.4 µM) and cytotoxic (EC50 ~ 12 µM) impacts on glioma and neuroblastoma cell lines suggest it is also a σ1 antagonist (2). PB28 also stopped cell growth in MCF7 breast cancer lines, and was synergistic with doxorubicin (3). PB28 also inhibited Kv2.1 channels in a σ-independent manner, suggesting it may be seen in future Alzheimer’s and diabetes research (4). Recently, PB28 showed potent (IC50 = 280 nM; 20-fold more than hydroxychloroquine) anti-SARS-CoV2 activity, without cardiac side effects (5,6).

References:

1) F Berardi et al. J. Med. Chem. 2004 47:2308

2) NA Colabufo et al. Naunyn Schmiedebergs Arch. Pharmacol. 2004 370:106

3) A Azzariti et al. Mol. Cancer Ther. 2006 5:1807

4) XY Liu et al. Oncotarget 2017 8:59345

5) DE Gordon et al. Nature 2020 583:459

6) C Abate et al. Front. Pharmacol. 2020 11:589810