PLoS One. 2013; 8(9): e74363.Published online 2013 September 3. doi: 10.1371/journal.pone.0074363PMCID: PMC3760846Pinellia pedatisecta Agglutinin Targets Drug Resistant K562/ADR Leukemia Cells through Binding with Sarcolemmal Membrane Associated Protein and Enhancing Macrophage PhagocytosisAgglutinin Targets Drug Resistant K562/ADR Leukemia Cells through Binding with Sarcolemmal Membrane Associated Protein and Enhancing Macrophage PhagocytosisAgglutinin Targets Drug Resistant K562/ADR Leukemia Cells through Binding with Sarcolemmal Membrane Associated Protein and Enhancing Macrophage PhagocytosisAgglutinin Targets Drug Resistant K562/ADR Leukemia Cells through Binding with Sarcolemmal Membrane Associated Protein and Enhancing Macrophage PhagocytosisAgglutinin Targets Drug Resistant K562/ADR Leukemia Cells through Binding with Sarcolemmal Membrane Associated Protein and Enhancing Macrophage Phagocytosis College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou, Zhejiang, ChinaAgglutinin Targets Drug Resistant K562/ADR Leukemia Cells through Binding with Sarcolemmal Membrane Associated Protein and Enhancing Macrophage PhagocytosisKan Chen, Xinyan Yang, Liqin Wu, Meilan Yu, Xiaoyan Li, Na Li, Shuanghui Wang, andGongchu Li*Sophia N Karagiannis, EditorAuthor information Article notes Copyright and License information Go to:AbstractPinelliapedatisecta agglutinin (PPA) has previously been used in labeling fractions of myeloid leukemia cells in our laboratory. We report here that a bacterial expressed recombinant PPA domain b tagged with soluble coxsackie and adenovirus receptor (sCAR-PPAb) preferentially recognized drug resistant cancer cells K562/ADR and H460/5Fu, as compared to their parental cell lines. Pretreatment of K562/ADR cells with sCAR-PPAb significantly enhanced phagocytosis of K562/ADR by macrophages in vivo. Meanwhile, in a K562/ADR xenograft model, intratumoral injection of sCAR-PPAb induced macrophage infiltration and phagocytosis. Furthermore, immunoprecipitation, mass spectrometry and Western blot identified the membrane target of PPA on K562/ADR as sarcolemmal membrane associated protein (SLMAP). An antibody against SLMAP significantly promoted the phagocytosis of K562/ADR by macrophages in vitro. These findings suggest that PPA not only could be developed into a novel agent that can detect drug resistant cancer cells and predict chemotherapy outcome, but also it has potential value in immunotherapy against drug resistant cancer cells through inducing the tumoricidal activity of macrophages.Go to:IntroductionResistance to anticancer drugs is a major factor resulting in the failure of chemotherapy. Cancer drug resistance is usually characterized by multiple drug resistance, or multidrug resistance (MDR), a phenomenon whereby cancers resistant to one drug are found to be resistant to other drugs with quite different structures and action modes 1. The identification of membrane transporters provided the first significant advance in understanding MDR. P-glycoprotein and other ATP-binding cassette (ABC) family members catalyze the efflux of anticancer drugs thereby leading to drug resistance 1,2. In recent years, a minor population of cancer cells, named cancer stem cells, with the self-renewal capacity, expression of ABC family members, and resistance to apoptosis became a new factor responsible for MDR 3,4,5. In addition, niche microenvironment hosting cancer cells provides components which lead to insensitivity of cancer cells to anticancer drugs 6,7. Recently, glycosylation changes have been found to be correlated with MDR 8, providing a new feature for cancer drug resistance.Analyzing the altered glycosylation of cancer cells in different stages of cancer progression may provide biomarkers for various cancers. In addition to antibodies recognizing specific oligosaccharides, lectins provide an alternative tool for glycosylation analysis 9. To date, a variety of lectin-based methods have been developed in examining cancer samples. Labeled lectins and lectin microarrays, combined with other technologies such as flow cytometry and proteomic analysis, have been used in identifying biomarkers for various cancers, which include Pancreatic cancer 10, prostate cancer 11, aggressive breast cancer 12,13, ovarian cancer 14, and liver cancer 15. Cancer stem cells from glioblastoma were reported to be recognized by lectins specific for -N-acetylgalactosamine, -N-acetylglucosamine, or galactose 16,17. Furthermore, lectins including Maackiaamurensis seeds lectin (MASL) 18, Concanavalin A 19, Polygonatumcyrtonema lectin 20, and various other lectins 21 have been developed into anticancer agents through inducing apoptosis or autophagy. In our laboratory, a mannose specific plant lectin,Pinelliapedatisecta agglutinin (PPA), has been shown to induce cancer cell death through an adenoviral vector-based gene delivery system, and th