Studies with 2,5-piperazinedione, 3,6-bis(5-chloro-2-piperidyl)-,dihydrochloride. I. Cell kinetic and biologic effects in cultured L1210, human epidermoid No. 2, and adenocarcinoma 755 cells.

: Experimental results obtained with cultured L1210, human epidermoid No. 2, and Adenocarcinoma 755 cells are consistent in showing that inhibition of proliferation of the cells by 2,5-piperazinedione, 3,6-bis(5-chloro-2-piperidyl)-,dihydrochloride is accompanied by cell enlargement. Although cells initially in the G2 phase when exposure to the agent is begun can probably proceed through mitosis and divide, cells that are initially in G1 and S phases accumulate in the G2 phase. Progression of cells to G2 phase during the period of exposure to the agent is not a requisite for cell-killing, because cells exposed for periods insufficient to permit their accumulation in G2 are killed.