In the forced swim test (FST) rodents progressively show increased episodes of immobility if immersed in a beaker with water from where escape is not possible. In this test, a compound qualifies as a potential antidepressant if it prevents or delays the transition to this passive (energy conserving) behavioural style. In the past decade however the switch from active to passive "coping" was used increasingly to describe the phenotype of an animal that has been exposed to a stressful history and/or genetic modification. A PubMed analysis revealed that in a rapidly increasing number of papers (currently more than 2,000) stress-related immobility in the FST is labeled as a depression-like phenotype. In this contribution we will examine the different phases of information processing during coping with the forced swim stressor. For this purpose we focus on the action of corticosterone that is mediated by the closely related mineralocorticoid receptors (MR) and glucocorticoid receptors (GR) in the limbic brain. The evidence available suggests a model in which we propose that the limbic MR-mediated response selection operates in complementary fashion with dopaminergic accumbens/prefrontal executive functions to regulate the transition between active and passive coping styles. Upon rescue from the beaker the preferred, mostly passive, coping style is stored in the memory via a GR-dependent action in the hippocampal dentate gyrus. It is concluded that the rodent's behavioural response to a forced swim stressor does not reflect depression. Rather the forced swim experience provides a unique paradigm to investigate the mechanistic underpinning of stress coping and adaptation.
Background: The tumor pyruvate kinase M2 (PKM2) is involved in the glycolytic pathway of lung cancer and targeting this kinase has been observed to radiosensitize non-small cell lung cancer (NSCLC).
Objective: An integration of in silico virtual screening and in vitro kinase assay was described to discover novel PKM2 inhibitors from a candidate library containing >400,000 commercially available compounds.
Method: The method is a stepwise screening scheme that first used empirical strategies to fast exclude those undruggable compounds in the library and then employed molecular docking and molecular dynamics (MD)-based rescoring to identify few potential hits. Subsequently, the computational findings were substantiated using a standard kinase assay protocol.
Results: Four compounds, i.e. nalidixic acid, indoprofen, hematoxylin and polydatin, were identified to inhibit PKM2 kinase at micromolar level, with IC50 values of 53, 21, 340 and 128 .M, respectively.
Conclusion: Structural analysis revealed that hydrogen bonds, salt bridges, π-π stacking and hydrophobic forces co-confer high stability and strong specificity to PKM2-inhibitor binding.