Although it was not possible to find reports on the induction of apoptosis by piperine by itself in MDR cells, piperine (concentration range of 50–200 μM) promoted apoptosis and caspase-3 cleavage in other experimental cancer models, such as melanoma [50,51], oral squamous cell carcinoma [52], human cervical adenocarcinoma [53], and gastric cancer [54]. Here, CASP3 is linked to oral cavity squamous cell carcinoma.