Cytotoxic effect of pumpkin (Curcurbita pepo) seed extracts in LNCaP prostate cancer cells is mediated through apoptosis

• Published in: Current topics in nutraceuticals research 2013-11, Vol.11 (4), p.137
• Main Authors: Rathinavelu, A, Levy, A, Sivanesan, D, Murugan, D, Jornadal, J, Quinonez, Y, Jaffe, M, Gossell-Williams, M
• Format: Article
• Language: English
• Subjects: Apoptosis; Cancer cells; Men; Prostate cancer; Pumpkins; Seeds
• ISSN: 1540-7535; 2641-452X

The cytotoxic effects and related mechanisms of pumpkin (Cucurbita pepo) seed ethanolic (PS-ET) and aqueous (PS-AQ) extracts were evaluated in LNCaP prostate cancer cells. LNCaP cells were exposed to extracts for 24hr. The viability of LNCaP cells was significantly decreased following 24 hr treatment with both PS-AQ (IC^sub 50^= 49 μg/ml) and PS-ET (IC^sub 50^= 55 μg/ml) extracts. The reactive oxygen species levels were also significantly increased (4.1 ± 0.2 and 3 ± 0.3 fold) and mitochondrial membrane potential was reduced with both PS-AQ and PS-ET extracts respectively. Both extracts induced DNA fragmentation and PolyADP-ribose polymerase (PARP) cleavage. Additionally PS-ET produced a 5 (± 0.2) and 3.5 (± 0.4) fold increase in caspase 3 and 9 activities respectively, while PS-AQ produced a 7 (± 0.4) and 3 (± 0.9) fold increase in caspase 3 and 9 activities respectively. Our results confirm that the cytotoxic activity of both PS extracts is mediated through oxidative stress and mitochondrial depolarization. Further, the cleavage of PARP, caspase activation and DNA fragmentation confirms the induction of apoptosis as the major cytotoxic modality for the extracts. These findings could hold positive implications for potential pumpkin seed extract intervention in prostate cancer therapy.