Cancer: Colon, breast, liver metastasis
Action: Induces apoptosis, MDR
Lunasin is a peptide found in soy, barley, wheat, and rye, including Glycine max [(L.) Merr.], Hordeum vulgare L., Triticum (L.) genus and Secale cereale L.
Colon Cancer; Metastasis
Lunasin bound with α(5)β(1) integrin and internalized into the nucleus of KM12L4 human colon cancer cells. Lunasin (10µM) inhibited the activation of focal adhesion kinase (FAK) by 28%, 39% and 60% in RKO, HCT-116 and KM12L4 human colon cancer cells, respectively. Lunasin caused an increase in the expression of the inhibitor of kappa B alpha (IκB-α), a decrease in nuclear p50 NF-κB and a reduction in the migration of cancer cells. Lunasin (4mg/kg bw) inhibited metastasis and potentiated the effect of oxaliplatin by reducing the expression of proliferating cell nuclear antigen.
Liver metastatic nodules were reduced from 28 (PBS) to 14 (lunasin, P=0.047) while combination of lunasin and oxaliplatin to 5 (P=0.004). The tumor burden was reduced from 0.13 (PBS) to 0.10 (lunasin, P=0.039) to 0.04 (lunasin+oxaliplatin, P<0.0001). Moreover, lunasin potentiated the effect of oxaliplatin in modifying expression of proteins involved in apoptosis and metastasis including Bax, Bcl-2, IKK-α and p-p65. Lunasin inhibited metastasis of human colon cancer cells by direct binding with α(5)β(1) integrin suppressing FAK/ERK/NF-κB signaling, and potentiated the effect of oxaliplatin in preventing the outgrowth of metastasis (Dia et al., 2011).
Induces Apoptosis
Galvez et al. (2001) demonstrated previously that transfection of mammalian cells with the lunasin gene arrests mitosis, leading to cell death. Here they show that exogenous application of the lunasin peptide inhibits chemical carcinogen-induced transformation of murine fibroblast cells to cancerous foci. The results suggest a mechanism whereby lunasin selectively induces apoptosis, mostly in cells undergoing transformation, by preventing histone acetylation. In support of this, lunasin selectively induces apoptosis in E1A-transfected cells but not in nontransformed cells. Finally, in the SENCAR mouse skin cancer model, dermal application of lunasin (250 microg/week) reduces skin tumor incidence by approximately 70%, decreases tumor yield/mouse, and delays the appearance of tumors by 2 weeks relative to the positive control. These results point to the role of lunasin as a new chemo-preventive agent that functions possibly via a chromatin modification mechanism.
Breast Cancer
Combinations of two or more chemo-preventive agents are currently being used to achieve greater inhibitory effects on breast cancer cells. This study reveals that both aspirin and lunasin inhibit, in a dose-dependent manner, human estrogen-independent breast cancer MDA-MB-231 cell proliferation.
These compounds arrest the cell-cycle in the S- and G1-phases, respectively, acting synergistically to induce apoptosis. The cell growth-inhibitory effect of a lunasin/aspirin combination is achieved, at least partially, by modulating the expression of genes encoding G1 and S-phase regulatory proteins. Lunasin/aspirin therapy exerts its potent pro-apoptotic effect, at least partially achieved through modulating the extrinsic-apoptosis dependent pathway.
Therefore, our results suggest that a combination of these two compounds is a promising strategy to prevent/treat breast cancer (Hsieh et al., 2010).
Colon Cancer; MDR
Various human colon cancer cell lines which underwent metastasis were evaluated in vitro using cell flow cytometry and fluorescence microscopy. Lunasin cytotoxicity to different colon cancer cells correlated with the expression of α5b1 integrin was investigated, being most potent to KM12L4 cells (IC50 = 13 µM). Lunasin arrested cell-cycle at G2/M phase with concomitant increase in the expression of cyclin-dependent kinase inhibitors p21 and p27. Lunasin (5–25 µM) activated the apoptotic mitochondrial pathway as evidenced by changes in the expressions of Bcl-2, Bax, nuclear clusterin, cytochrome c and caspase-3 in KM12L4 and KM12L4-OxR.
Lunasin increased the activity of initiator caspase-9 leading to the activation of caspase-3 and also modified the expression of human extracellular matrix and adhesion genes, down-regulating integrin α5, SELE, MMP10, integrin β2 and COL6A1 by 5.01-, 6.53-, 7.71-, 8.19- and 10.10-fold, respectively, while up-regulating COL12A1 by 11.61-fold. Lunasin can be used in cases where resistance to chemotherapy developed (Dia et al., 2011).
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