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There exists compelling evidence that Toll-like receptor 3 (TLR3) agonists can directly affect human cancer cells. The aim of this study was to investigate anti-cancer effects of TLR3 agonist in human breast cell line. We assessed potential effects of poly (A:U) on human breast cell line (MDA-MB-231) on a dose-response and time-course basis. Human breast cell line MDA-MB-231 was treated with different concentrations of poly (A:U) and lipopolysaccharide (LPS). Then, the following assays were performed on the treated cells: dose-response and time-course cytotoxicity using colorimetric method; matrix metalloproteinase-2 (MMP-2) activity using gelatin zymography method; apoptosis using annexin-v flowcytometry method; and relative expression of TLR3 and MMP-2 mRNA using reverse transcriptase polymerase chain reaction (RT-PCR) method. Following treatments, dose- response and time-course cytotoxicity using a colorimetric method, (MMP-2) activity (using gelatin zymography), apoptosis (using annexin-v flowcytometry method) assays and expression of TLR3 and MMP-2 genes (using PCR method) were performed. Cytotoxicity and flowcytometry analysis of poly (A:U) showed that poly (A:U) do not have any cytotoxic and apoptotic effects in different concentrations used. MMP-2 activity analysis showed significant decrease in higher concentrations (50 and 100 µg/ ml) between treated and untreated cells. Moreover, poly A:U treated cells demonstrated decreased expression of MMP-2 gene in higher concentrations. Collectively, our data indicated that human breast cancer cell line (MDA-MB-231) was highly responsive to poly (A:U). The antimetastatic effect of direct poly (A:U) and TLR3 interactions in MDA-MB-231 cells could provide new approaches in malignant tumor therapeutic strategy.

Controversial immunomodulatory properties of bee venom (BV) have provided an appropriate field for more investigation. The aim of present research was to verify the effects of honeybee venom on matrix metalloproteinase activity and interferon production as well as cell proliferation in monocyte and fibroblast cell lines. The monocyte and fibroblast cell lines (K562, HT-1080, WEHI-164) were used in order to assess proliferative response, interferon-1 production and matrix metalloproteinase-2 (MMP-2) activity. Australian BV (ABV) and Iranian BV (IBV) preparations at concentrations of 0.025, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, and 1µg/ml were added to each overnight cultured cell. In time course study, cells were treated with each ABV and IBV. In all cases supernatants were collected 24 hours after treatment. A sample of the each medium was used for zymography and interferons assay. Non-treated cells were used as controls. The production of IFN- and IFN- in supernatant of cell culture was assessed using enzyme linked immunoassay procedure. MMP-2 activity, as an inflammatory index, was evaluated using zymoanalysis method. The results of this study showed that, there were no significant difference between two sources of honey bee venoms when they were added to an identical cell line, whereas, the responses of various cell lines against bee venom were different. The increasing amounts of bee venom to human monocyte cell line (K562) revealed a significant increase in proliferative response. Our findings showed that the bee venom had no influence on IFN- production in cell culture media, whereas, adding the BV to K562 cell line could significantly increase the production level of IFN- only on day 8 post-treatment. In addition the effect of bee venom on MMP-2 activity in both cell culture media, WEHI-164 and K562 was similar. The stimulatory effect of bee venom on MMP-2 activity occurred at low doses. In contrast, its inhibitory effect was seen at high concentrations. It is concluded that, honeybee venom affects on MMP-2 activity and interferon beta production as well as cell proliferation in a time and dose-dependent manner.