Apoptotic Killing of Breast Cancer Cells by IgYs Produced Against a Small 21 Aminoacid Epitope of the Human TRAIL-2 Receptor

TRAIL, tumor necrosis factor (TNF)-related apoptosis-inducing ligand belongs to one of important cytokine superfamilIES, tumor necrosis factor (TNFα) . TRAIL-2 receptor agonists activate several cell signaling pathways in cells in different manners and could lead to apoptosis or necrosis. Agonistic egg yolk antibodies like IgY which have been developed in a selective manner could activate TRAIL death receptors such as TRAIL-2 (DR5) and thus apoptosis signaling. We here investigated induction of apoptosis in human breast cancer cells (MCF7 cell line) by an IgY produced against an 21 aminoacid epitope of the human TRAIL-2 receptor. As the first step a small peptide of 21 aminoacids choosen from the extracellular domain of DR5 protein was produced with a peptide synthesizer. After control assays and confirmation of the correct amino acid sequence, it was injected to hens immunized to achieve high affinity IgYs. At the next step, the produced IgYs were extracted and examined for specificity against DR5 protein by ELISA assay. Subsequently, the anticancer effect of such IgYs was determined by MTT assay in the MCF7 human breast cancer cell line. The produced peptides successfully immunized hens and the produced antibodies which accumulated in egg yolk specifically recognized the DR5 protein. IgYs exerted significant toxicity and killed MCF7 cells as shown by MTT assay.

Cytotoxicity Effects of Mouse IgG Produced against Three Nanoliposomal Human DR5 Receptor Epitopes on Breast Cancer Cells

Cancer causes cells to avoid death while being the second cause of death in the world itself. Damaged cells in the absence of apoptosis will increasingly amplify their inefficient genome. Of the two main apoptosis inducing pathways in cells, the first has p53 protein as the main initiating factor in the cascade. According to research results this protein s mutated in 50% of cancers and sointerest has cooncentrated on the second pathway that features death receptors. Among these receptors TRAIL1/DR5 is especially expressed in cancer cells. So targeting such receptors can initiate the apoptotic cascade in cells. Interestingly by substitution of activating ligands with antibodies as agonists, we could efficiently turn on the apoptosis pathway. First of all, three small peptides from the DR5 protein extracellular domain were synthesized and injected with two different kind of adjuvants (Fround and liposomal encapsulation) separately into mice at 15 day intervals. As a result, liposomal peptides induced the immune system more efficient than Frounds adjuvant and at the end point the antibodies which were obtained from liposomal peptide injection induced much more effective death. Liposomal formol could be used as an adjuvant in immunization utilizing small peptides. They carry, protect and deliver peptides very efficiently. In addition, small peptides of a certain size from the extracellular domain of DR5 proteins not only can induce immune system but also produce antibodies playing a remarkable anti-cancer roles against breast cancer cells (MCF-7).