Porcine recombinant NK-lysin(Shanxi Agricultural University)

Natural killer (NK)-lysin, a broad-spectrum antimicrobial peptide, has antitumor and antibactericidal activities against both gram-positive and gram-negative bacteria. In this study the recombinant porcine NK-lysin was expressed and purified in the Pichia pastoris system, and then 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide was used to assess its anticancer activity in vitro. The results showed that the recombinant porcine NK-lysin possesses potent antitumor activity against the human hepatocellular carcinoma cell line SMMC-7721 in a time- and dose-dependent manner, but has negligible hemolysis activity against human erythrocytes. Scanning electronic microscopy was used to directly observe the ultrastructure of SMMC-7721 cells treated with NK-lysin; untreated cells showed lamellipodia and filopodia scattered with the cell surface, with good cell-cell contacts among neighboring cells. In contrast, treated tumor cells exhibited marked alterations in cell morphology, and cell-cell contacts disappeared among neighboring cells. Compared with the untreated tumor cells, the tumor cells treated with NK-lysin for 12 and 24 hr were suppressed for the expression of fascin 1. Thus, the recombinant porcine NK-lysin potentially could be developed as a therapeutic agent for inhibiting tumor growth.

Porcine recombinant NK-lysin (prNK-lysin) has been shown to inhibit the proliferation and metastasis of hepatocellular carcinoma (HCC) cells in vitro. However, its effects on the proliferation and metastasis of HCC cells in vivo remain unclear. In this study, an allograft murine model using the murine HCC cell line Hepa1-6 was employed to investigate the anticancer effects of prNK-lysin. Initially, the in vitro anticancer efficacy of prNK-lysin was evaluated in Hepa1-6 cells, demonstrating that prNK-lysin effectively inhibited both proliferation and metastasis. These effects were mediated through the induction of oncosis and suppression of Fascin-1, MMP-2, and MMP-9 protein expressions. Subsequently, the in vivo anticancer efficacy of prNK-lysin was assessed using a mouse liver orthotopic implantation model and a lung metastasis model of Hepa1-6 cells in BALB/cA-nu mice. The administration of 13 mg/kg of prNK-lysin could inhibit tumor growth in the liver and metastasis to the lungs. Our results demonstrate that prNK-lysin possesses strong anti-HCC effects both in vitro and in vivo, with the induction of oncosis and the inhibition of Fascin-1, MMP-2, and MMP-9 protein expressions as potential molecular mechanisms for its anticancer activity.