Structure Based Design and Synthesis of Peptide Inhibitor of Human LOX-12: In Vitro and In Vivo Analysis of a Novel Therapeutic Agent for Breast Cancer

Abstract

Human breast cancer cell proliferation involves a complex interaction between growth factors, steroid hormones and peptide hormones. The interaction of growth factors, such as epidermal growth factor (EGF), with their receptors on breast cancer cells can lead to the hydrolysis of phospholipids and release of fatty acid such as arachidonic acid, which can be further metabolized by cyclooxygenase (COX) and lipoxygenase (LOX) pathways to produce prostaglandins. The high concentration of prostaglandins has been associated with chronic inflammatory diseases and several types of human cancers. This is due to the over expression COX, LOX and other inflammatory enzymes. Ten peptides were designed and synthesized by solid phase peptide synthesis and analyzed in vitro for enzyme inhibition. Out of these peptides, YWCS had shown significant inhibitory effects. The dissociation constant (K D ) was determined by surface plasmon resonance (SPR) analysis and was found to be 3.39×10 −8 M and 8.6×10 −8 M for YWCS and baicalein (positive control), respectively. The kinetic constant Ki was 72.45×10 −7 M as determined by kinetic assay. The peptide significantly reduced the cell viability of estrogen positive MCF-7 and estrogen negative MDA-MB-231 cell line with the half maximal concentration (IC 50 ) of 75 µM and 400 µM, respectively. The peptide also induced 49.8% and 20.8% apoptosis in breast cancer cells MCF-7 and MDA-MB-231, respectively. The YWCS was also found to be least hemolytic at a concentration of 358 µM. In vivo studies had shown that the peptide significantly inhibits tumor growth in mice (p<0.017). This peptide can be used as a lead compound and complement for ongoing efforts to develop differentiation therapies for breast cancer.

Serum 5-LOX: a progressive protein marker for breast cancer and new approach for therapeutic target

“…These findings strongly supports that the serum level of 5-LOX can be a good blood-based non-invasive marker for the early detection of the breast cancer in the clinical setup. Previously, we reported the inhibition of 12-LOX, by YWCS peptide inhibitor, effectively induced cytotoxicity and apoptosis in MCF-7 and MDA-MB-231 breast cancer cells (11). As the active site of 12-LOX and 5-LOX are homologous, the same peptide YWCS were docked with the 5-LOX protein and found to have strong interaction in the binding site.…”

“…Numerous autonomous studies by different groups of researchers now support the correlation between the expression of 5-LOX and cancer cell viability, invasion through extracellular matrix destruction, cell migration, proliferation, metastasis and activation of anti-apoptotic signaling cascades, which makes the 5-LOX effective therapeutic regimen (28). The earlier evidences interpreted the efficacy of peptide, YWCS, to inhibit 12-LOX and its utilization as an anti-breast cancer molecule by inducing cytotoxicity and apoptosis in MCF-7 and MDA-MB-231 breast cancer cells (11). In this study, the peptide, YWCS was found to be active against 5-LOX also and thus adding further information regarding the mechanism through which it induce cytotoxicity in breast cancer cells.…”

“…This study focused on determination of serum level of 5-LOX protein in breast cancer patients and also analyzes the effect of 5-LOX protein by YWCS peptide inhibitor. YWCS is a small peptide inhibitor of 12-LOX which was reported in our previous study (11). Owing to the structural similarities in the active site of 12-LOX and 5-LOX (12), the effect of YWCS was assessed on 5-LOX.…”

Solid Phase Synthesis of Mitochondrial Triphenylphosphonium-Vitamin E Metabolite Using a Lysine Linker for Reversal of Oxidative Stress

“…The masked lysine was coupled onto the Rink Amide MBHA resin. HBTU and HOBt were used to enhance the coupling rate [55], [56], [57]. The Fmoc was then deprotected to allow for (3-carboxypropyl)TPP + conjugation through its carboxylic acid group forming an amide bond.…”

Simulation of Cake Filtration for Polydisperse Particles

“…In the past decade, the development of peptides and peptidomimetics as potential candidates to remedy various diseases has attracted considerable attention in both academia and the pharmaceutical industry 20,21,22. This is due to the high specificity, solubility, stability, and unique pharmacokinetic characteristics of peptides compared with large proteins or small molecules 23.…”