Fordin: A novel type I ribosome inactivating protein from Vernicia fordii modulates multiple signaling cascades leading to anti-invasive and pro-apoptotic effects in cancer cells in�vitro

Abstract

Fordin, which is derived from Vernicia fordii, is a novel type I ribosome inactivating protein (RIP) with RNA N-glycosidase activity. In the present study, fordin was expressed by Escherichia coli and purified using nickel affinity chromatography. Previous studies have demonstrated RIP toxicity in a variety of cancer cell lines. To understand the therapeutic potential of fordin on tumors, the present study investigated the effects of fordin on the viability of several tumor and normal cell lines. The results demonstrated that fordin induced significant cytotoxicity in four cancer cell lines, compared with the normal cell line. Specifically, profound apoptosis and inhibition of cell invasion were observed following fordin exposure in U-2 OS and HepG2 cells; however, the molecular mechanism underlying the action of RIP remains to be fully elucidated. In the present study, it was found that the anticancer effects of fordin were associated with suppression of the nuclear factor (NF)-κB signaling pathway. In U-2 OS and HepG2 cells, fordin inhibited the expression of inhibitor of NF-κB (IκB) kinase, leading to downregulation of the phosphorylation level of IκB, which quelled the nuclear translocation of NF-κB. Fordin also reduced the mRNA and protein levels of NF-κB downstream targets associated with cell apoptosis and metastasis, particularly B-cell lymphoma-2-related protein A1 (Blf-1) and matrix metalloproteinase (MMP)-9. The inactivation of NF-κB and the reduction in the expression levels of Blf-1 and MMP-9 mediated by fordin were also confirmed by co-treatment with lipopolysaccharide or p65 small interfering RNA. These findings suggested a possible mechanism for the fordin-induced effect on tumor cell death and metastasis. The results of the present study demonstrated the multiple anticancer effects of fordin in U-2 OS and HepG2 cells, in part by inhibiting activation of the NF-κB signaling pathway.

The type-1 ribosome-inactivating protein OsRIP1 triggers caspase-independent apoptotic-like death in HeLa cells

“…In previous studies, the type 1 RIPs from Malus domestica (Shang et al, 2016) and Curcin C (Lin et al, 2003) were not toxic to HeLa cells or NHDF cells. Other type 1 RIPs, such as Fordin (Lu et al, 2018), MAP30 (Lv et al, 2015) and Trichosanthin (Lin et al, 2017), showed moderate cytotoxicity with higher IC 50 values than OsRIP1. When MAP30 and Trichosanthin were fused to a penetrating peptide (HBD or S3) to enhance uptake in the cell, they were still less toxic for HeLa cells compared to recombinant OsRIP1 (Supplementary Table S6) (Lin et al, 2017;Lv et al, 2015;Song et al, 2018).…”

Exploiting yoeB‐yefM toxin‐antitoxin system of Streptococcus pneumoniae on the selective killing of miR‐21 overexpressing breast cancer cell line (MCF‐7)

“…Although it has not been established, the YoeB toxin might probably act similarly in eukaryotic cells, especially considering that such proteins (known as ribosome-inactivating proteins [RIPs]) are recognized which display activity in both prokaryotic and eukaryotic cells (Yamamoto et al, 2002). In addition, several lines of evidence support that some RIPs are able to promote mammalian cell death by apoptosis induction (Lu et al, 2018;Narayanan, Surendranath, Bora, Surolia, & Karande, 2005;Walsh, Dodd, & Hautbergue, 2013). However, our qRT-PCR results indicated that the expression of P53, caspase-7, caspase-9, Bax, and Bak is not altered in transfected and untransfected MCF-7 cells and thus, it According to the high basal expression of miR-21 in MCF-7 cells, the toxin module, YoeB could induce programmed cell death in mammalian cells, an effect that is neutralized by expression of its cognate antitoxin, YefM, in non-tumoral MCF-10A cells.…”