Breast Cancer Targeting Peptide Binds Keratin 1: A New Molecular Marker for Targeted Drug Delivery to Breast Cancer

Abstract

The biomarkers or receptors expressed on cancer cells and the targeting ligands with high binding affinity for biomarkers play a key role in early detection and treatment of breast cancer. The breast cancer targeting peptide p160 (12-mer) and its enzymatically stable analogue 18-4 (10-mer) showed marked potential for breast cancer drug delivery using cell studies and animal models. Herein, we used affinity purification, liquid chromatography-tandem mass spectrometry, and proteomics to identify keratin 1 (KRT1) as the target receptor highly expressed on breast cancer cells for p160 peptide(s). Western blot and immunocytochemistry in MCF-7 breast cancer cells confirmed the identity of KRT1. We demonstrate that the p160 or 18-4 binding to MCF-7 breast cancer cells is dependent on the expression of KRT1, and we confirm peptide-KRT1 binding specificity using SPR experiments (K ∼ 1.1 μM and 0.98 μM for p160 and 18-4, respectively). Furthermore, we assessed the ability of peptide 18-4 to improve the cellular uptake and anticancer activity of a pro-apoptotic antimicrobial peptide, microcin J25 (MccJ25), in breast cancer cells. A covalent conjugate of peptide 18-4 with MccJ25 showed preferential cytotoxicity toward breast cancer cells with minimal cytotoxicity against normal HUVEC cells. The conjugate inhibited the growth of MDA-MB-435 MDR multidrug-resistant cells with an IC comparable to that of nonresistant cells. Conjugation improved selective cellular uptake of MccJ25, and the conjugate triggered cancer cell death by apoptosis. Our findings establish KRT1 as a new marker for breast cancer targeting. Additionally, it pinpoints the potential use of antimicrobial lasso peptides as a novel class of anticancer therapeutics.

Synthesis of breast cancer targeting conjugate of temporin-SHa analog and its effect on pro- and anti-apoptotic protein expression in MCF-7 cells

“…The deleterious side effects on healthy cells and tissues cause toxicity towards vital organs and severe inflammatory responses due to necrosis [1][2][3][4]. To improve the selectivity of therapeutic agents, one strategy involves conjugation of the cytotoxic drug with targeting ligands such as antibodies or tumor targeting peptides that recognize specific receptors on particular types of cancer cells [5][6][7][8][9][10][11][12]. Recently, a decapeptide sequence WXEAAYQXFL, with varied residues at X positions, was discovered to promote specific binding to breast cancer cell lines [10][11][12].…”

“…To improve the selectivity of therapeutic agents, one strategy involves conjugation of the cytotoxic drug with targeting ligands such as antibodies or tumor targeting peptides that recognize specific receptors on particular types of cancer cells [5][6][7][8][9][10][11][12]. Recently, a decapeptide sequence WXEAAYQXFL, with varied residues at X positions, was discovered to promote specific binding to breast cancer cell lines [10][11][12]. One of these breast cancer targeting peptides (BCTP), with D-norleucine and D-arginine residues in positions 2 and 8 respectively, was modified (r8k and C-terminal carboxyamidation) and then conjugated with the cytotoxic anticancer drug doxorubicin.…”

Design and Evaluation of Gemini Surfactant-Based Lipoplexes Modified with Cell-Binding Peptide for Targeted Gene Therapy in Melanoma Model

“…(9, 10) p18-4 specifically interacts with overexpressed KRT-1 in MDA-MB-435 and MCF-7 cells. (34) In the current work, we evaluated the ability of p18-4 modified lipoplexes to target melanoma using a model cell line (A375) showing overexpression of keratins. (35,36) The increase in gene expression by the p18-4 modified lipoplexes could be attributed to the specific interaction of p18-4 with keratins and lead to improvement of cellular uptake of the lipoplexes and higher transfection activity [ Figure 3 A].…”

Identification of key molecular targets that correlate with breast cancer through bioinformatic methods

“…In addition, the targeted delivery of Polo‐like kinase 1 siRNA was considered to be a novel nanoparticle platform with intrinsic antimetastatic properties . Based on the results of affinity purification, liquid chromatography–tandem mass spectrometry and proteomics, keratin 1 was identified as the target receptor highly expressed on breast cancer cells . Accordingly it was of great significance to investigate its pathogenesis from the perspective of molecular biology.…”

“…8 Based on the results of affinity purification, liquid chromatography-tandem mass spectrometry and proteomics, keratin 1 was identified as the target receptor highly expressed on breast cancer cells. 9 Accordingly it was of great significance to investigate its pathogenesis from the perspective of molecular biology. The present study comprehensively analyzed the gene expression profiles of several breast cancer, and screened the important gene factors related to breast cancer.…”