Insights into the Mode of Action of Novel Morpholinated Curcumin Derivatives Exhibiting Potent Antitumor Activity in Bladder Cancer Cells In Vitro.

Although curcumin is a well-known natural polyphenol with many biological activities, its clinical application has been limited by low aqueous solubility and stability. Therefore, curcumin derivatives have been proposed to overcome these limitations and increase anticancer activity. This study tested curcumin derivatives with modified feruloyl moieties ( and ) and the β-diketo moiety () to better understand their anticancer mechanism against human bladder cancer cells. The anticancer activity of and was determined using MTT (hypoxic conditions) and LDH (normoxic conditions) assays. An ELISA-based protein panel was used to find the potential molecular targets, while flow cytometric, colorimetric, fluorescent, and luminescent assays were used to investigate the cell death mechanism. It was shown that compound exerted a more potent cytotoxic effect under hypoxic conditions, while compound demonstrated a comparable effect in normoxic and hypoxic conditions. The potential molecular targets modified by and depending on oxygen concentration were also proposed. Both compounds alter cell cycle progression by blocking the cell cycle in the G2/M phase and decreasing the percentage of cells in the G0/G1 phase. Compound led to phosphatidylserine translocation, increased caspase 3/7 activity, and decreased mitochondrial membrane potential, suggesting a mitochondrial apoptosis pathway. We found that the Akt signaling pathway may modulate the activity of compound , as evidenced by enhanced cytotoxic activity in combination with MK-2206, an Akt 1/2/3 inhibitor. Thus, our results provide new insights into the anticancer activity of compounds and ; however, further studies are needed to better understand their therapeutic potential.