pardaxin and Fibrosarcoma

The antitumor activity of pardaxin, a fish antimicrobial peptide, has not been previously examined in in vitro and in vivo systems for treating murine fibrosarcoma. In this study, the antitumor activity of synthetic pardaxin was tested using murine MN-11 tumor cells as the study model. We show that pardaxin inhibits the proliferation of MN-11 cells and reduces colony formation in a soft agar assay. Transmission electron microscopy (TEM) showed that pardaxin altered the membrane structure similar to what a lytic peptide does, and also produced apoptotic features, such as hollow mitochondria, nuclear condensation, and disrupted cell membranes. A qRT-PCR and ELISA showed that pardaxin induced apoptosis, activated caspase-7 and interleukin (IL)-7r, and downregulated caspase-9, ATF 3, SOCS3, STAT3, cathelicidin, p65, and interferon (IFN)-γ suggesting that pardaxin induces apoptosis through the death receptor/nuclear factor (NF)-κB signaling pathway after 14 days of treatment in tumor-bearing mice. An antitumor effect was observed when pardaxin (25 mg/kg; 0.5 mg/day) was used to treat mice for 14 days, which caused significant inhibition of MN-11 cell growth in mice. Overall, these results indicate that pardaxin has the potential to be a novel therapeutic agent to treat fibrosarcomas.

Topics: Animals; Antineoplastic Agents; Apoptosis; Cell Membrane; Cell Proliferation; Dose-Response Relationship, Drug; Enzyme-Linked Immunosorbent Assay; Female; Fibrosarcoma; Fish Venoms; Male; Mice; Mice, Inbred C57BL; Microscopy, Electron, Transmission; NF-kappa B; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction; Xenograft Model Antitumor Assays

Pardaxin, a pore-forming antimicrobial peptide that encodes 33 amino acids was isolated from the Red Sea Moses sole, Pardachirus mamoratus. In this study, we investigated its antitumor activity in human fibrosarcoma (HT-1080) cells and epithelial carcinoma (HeLa) cells. In vitro results showed that the synthetic pardaxin peptide had antitumor activity in these two types of cancer cells and that 15μg/ml pardaxin did not lyse human red blood cells. Moreover, this synthetic pardaxin inhibited the proliferation of HT1080 cells in a dose-dependent manner and induced programmed cell death in HeLa cells. DNA fragmentation and increases in the subG1 phase and caspase 8 activities suggest that pardaxin caused HeLa cell death by inducing apoptosis, but had a different mechanism in HT1080 cells.

Topics: Amino Acid Sequence; Animals; Apoptosis; Carcinoma; Caspase 8; Cell Proliferation; Cell-Penetrating Peptides; DNA Fragmentation; Erythrocytes; Female; Fibrosarcoma; Fish Proteins; Fish Venoms; Fishes, Poisonous; G1 Phase; HeLa Cells; Humans; Molecular Sequence Data; Neurotoxins; Organ Specificity; Up-Regulation

Pardaxin is an antimicrobial peptide (AMP) that was first isolated from secretions of the Red Sea Moses sole. The role of pardaxin in inducing apoptosis for preventing cancer has not yet been investigated. In the present study, we examined the antitumor activity of pardaxin against human fibrosarcoma HT-1080 cells; pardaxin inhibited cell proliferation by inducing apoptosis, as demonstrated by an increase in the externalization of plasma membrane phosphatidylserine and the presence of chromatin condensation. Additionally, pardaxin-treated cells showed elevation of caspase-3/7 activities, disruption of the mitochondrial membrane potential, and accumulation of reactive oxygen species (ROS) production. Inhibition of ROS production and caspase-3/7 activities reduced pardaxin-induced effects. Taken together, these findings suggest that pardaxin may be a potential anticancer agent for selectively inducing apoptosis in cancer cells.

Topics: Antimicrobial Cationic Peptides; Antineoplastic Agents; Apoptosis; Caspase 3; Caspase 7; Cell Line, Tumor; Cell Proliferation; Fibrosarcoma; Fish Venoms; Humans; Reactive Oxygen Species