Combination of the PI3K inhibitor copanlisib with the CDK4/6 inhibitor palbociclib did not induce apoptosis in MCL and MZL cell lines, but did induce G0/G1 arrest with upregulation of PIK3IP1. (A) Four cell lines were exposed for 24 hours to copanlisib (30 nM, 300 nM), palbociclib (0.3 μM, 3 μM), or the combination of the 2 agents. (B) Cell-cycle analysis of 1 MCL (JEKO1) and 1 MZL (SSK41) cell line exposed for 24 hours to copanlisib (30 nM, 300 nM), palbociclib (0.3 μM, 3 μM), or the combination of the 2 agents. (C) RNA changes of PIK3IP1 in 1 MCL (JEKO1) and 1 MZL cell line exposed for 24 hours to copanlisib (30 nM, 300 nM), palbociclib (0.3 μM, 3 μM), or the combination of the 2 agents.