Evaluation of mTOR, NFκB and BCL-2 Inhibitor Activity In Vitro in Karpas 1106P, a Primary Mediastinal B-Cell Lymphoma Cell Line

Introduction: PMBCL is an aggressive type of lymphoma characterized by high heterogeneity in clinical, molecular, and genetic features. In PMBCL, disturbances in the NFkB pathway and deregulation of BCL-2 and mTOR family proteins are observed, which may contribute to impaired apoptosis. Therefore, many strategies have been established to target the functioning of these pathways. Early clinical trials of mTOR, NFkB and Bcl-2 inhibitors suggest their activity in many hematological cancers, but their activity as monotherapy agents may still be insufficient; therefore, combinations of these compounds with other molecules acting on those active in a given cancer subtype are being sought. Materials and Methods: In vitro studies were conducted on a single PMBCL cell line, Karpas 1106P. We administered three novel drugs: AZD2014 (vistusertib), an inhibitor of the serine-threonine kinase mTOR; IMD-0354, an NFκB inhibitor; and ABT-199 (venetoclax), a highly selective inhibitor for BCL-2. Drugs were administered alone, in pairs and in combination of all three agents. Results: Based on the results of our own research, for the Karpas cell line individually, ABT-199 had the strongest pro-apoptotic effect on cancer cells, while in pairs the most potent induction of apoptosis occurred following treatment with AZD2014+ABT-199. The combination of three drugs did not have a stronger effect than either a single drug used alone or any two-drug combination. Conclusions: These results provide preliminary in vitro evidence that targeting the BCL-2 and mTOR pathways may enhance pro-apoptotic activity in a PMBCL cell model; however, further validation in additional cell lines and in vivo models is needed before translational implications can be considered.