Abstract:

Objective: To explore the antitumor effect of cuttlefish ink peptidoglycan (PGN) on PC-3 and DU-145 cells and
its mechanism in vitro. Methods: After PC-3 and DU-145 cells were treated by cuttlefish ink PGN, HE staining was used
to observe cell growth condition and morphology, FCM was used to observe cell apoptosis, immunocytochemical staining
(SABC) was used to analyze the expression of COX-2 and VEGF proteins and in situ hybridization was used to analyze the
mRNA expression of Bcl-2 Caspase-3. The expression of COX-2, VEGF, Bcl-2 and Caspase-3 in the two human prostate
cancer cell lines were also examined using western blot. Results: Morphological features of apoptosis, and the early stage
of apoptosis in treated cells was observed in a dose-dependent manner. Moreover, cuttlefish ink peptidoglycan exposure for
24 h could result in a decease in the expression of COX-2, VEGF and Bcl-2 and an increase in the expression of Caspase-3.
Conclusion: Cuttlefish ink peptidoglycan can induce the apoptosis of PC-3 and DU-145 cells possibly by down-regulating
the expression of COX-2 and VEGF proteins and Bcl-2 mRNA and up-regulating the expression of Caspase-3 mRNA.

Key words: cuttlefish ink peptidoglycan, PC-3 cell line, DU-145 cell line, apoptosis