Diluted povidone-iodine inhibits tumor growth through apoptosis-induction and suppression of SOD activity

Abstract

Abstract. Povidone-iodine (PVP-I) is widely used in clinical practice as an antiseptic and flushing agent after surgery to remove a tumor. Our present study was designed to determine whether diluted PVP-I is cytotoxic to colon cancer cells and ascetic tumor cells in vitro and to examine its antitumor effects in vivo. In vitro, CT26 and H22 cells treated with different concentrations of diluted PVP-I (0-1.56 µg/ml) were analyzed using the mononuclear cell direct cytotoxicity assay (MTT) and a flow cytometry assay. In vivo, Balb/c mice injected in the abdominal cavity with CT26 cells or H22 cells were treated intraperitoneally with different concentrations of PVP-I (0-312.5 µg/mouse), cisplatin (40 mg/kg) or 5'-FU (30 mg/kg) or left untreated. In vitro, the studies demonstrated the antiproliferative and significant apoptosis-inducing effects of PVP-I in a dose-and time-dependent manner. In vivo, PVP-I significantly repressed the growth of H22 and CT26 cells in Balb/c mice compared to controls. To explore the mechanism of the antitumor effect of PVP-I, the superoxide dismutase (SOD) activity of ascites extracted from a mouse model and the supernatant of CT26 cells was detected by an SOD kit. The activity of SOD was significantly inhibited in the experimental groups. Taken together, our data suggest that PVP-I exhibits a strong inhibitory effect on tumor growth in colon cancer (CT26) and hepatoma (H22) resulting from apoptosis, both in vitro and in vivo, suggesting a new potential therapeutic approach after tumor excision surgery to colon cancer and hepatoma. IntroductionColorectal cancer and hepatoma, the most common malignant tumors worldwide, are responsible for a great number of cancer deaths (1-4). Excisional surgery, the most effective therapy in achieving cure, plays an important part in the management of these cancers (5). Owing to port-site metastases, the benefits of laparoscopic surgery which is the primary treatment modality for colorectal cancer are uncertain (6). Balli et al (7) have described a technique for preventing port-site metastases based on their 8-year experience with laparoscopic surgery for colorectal cancer. In this 6-step technique use of 5% povidoneiodine (PVP-I) intraluminal irrigation and intraoperative colonoscopy are an important routine (7). Moreover, another laparoscopic experimental study showed that the PVP-I solution resulted in almost zero implantation rate at trocar sites, as compared with other cytotoxic agents (8). These findings suggest that PVP-I probably has anti-tumor activity.PVP-I, a broad spectrum microbicide against bacteria, virus, fungi and parasites in vitro (9-12), consists of elementary iodine bound to the carrier poly (1-vinyl-2-pyrrolidone) that enhances the solubility and gives a depot of iodine (13). Based on the oxidizing effects of free iodine on NH-and SH-OH-groups of amino acids and on double bonds of unsaturated fatty acids, PVP-I showed the ability of non-specifically inducing cell death (14). Previous studies have demonstrated that PVP-I had anti-tumo...

Electrospun Fibers and Sorbents as a Possible Basis for Effective Composite Wound Dressings

“…The improvement of antimicrobial activity for PCL/PVP 85:15 scaffold compared with pure PCL fibers could be associated with the prolonged release of PVP. As observed in tumor cells, PVP could interfere with SOD and other antioxidant enzymes of bacterial and fungus to produce growth inhibition [96,98]. The faster dissolution of pure PVP fibers could be the reason not to observe the antimicrobial activity.…”