Forskolin Increases cAMP Levels and Enhances Recombinant Antibody Production in CHO Cell Cultures

Cyclic adenosine monophosphate (cAMP) is a ubiquitous second messenger essential to many biological processes. Forskolin, a labdane diterpene, is widely used to increase cAMP levels in various cell types. When 5 mu mof forskolin is added to recombinant Chinese hamster ovary (rCHO) cell cultures producing monoclonal antibody (mAb) (GSR cell line), it decreases specific growth rate (mu), but increases culture longevity and specific mAb productivity (q(mAb)). The beneficial effect of forskolin on culture longevity andq(mAb)outweighs its detrimental effect on mu, resulting in 1.5-fold increase in the maximum mAb concentration (MMC) without an adverse effect on mAb quality attributes such as aggregation, charge variation, and galactosylation. Forskolin induces cell cycle arrest at the G0/G1 phase via the LKB1/AMPK pathway and inhibits apoptosis via the CREB/Bcl-2 pathway. The beneficial effect of forskolin on mAb production is also demonstrated with another rCHO cell line (ABTAA). Addition of 5 mu mforskolin to ABTAA cell cultures also results in 1.5-fold increase in the MMC. Taken together, the results obtained demonstrate that forskolin is an efficient chemical reagent to increase mAb production in rCHO cell cultures.