PLD2 and lung adenocarcinoma: To further confirm whether endogenous SIRT1 and PLD isozymes can form a natural complex in colorectal cancer cells (HT119 and HT29 cells) and A549 lung adenocarcinoma cells, which express both endogenous PLD1 and PLD2 (Fig. 1d), we performed coimmunoprecipitation assays.