Alterations in Glycopeptides Associated with Herceptin Treatment of Human Breast Carcinoma MCF-7 and T-Lymphoblastoid Cells

Abstract

The therapeutic humanized monoclonal antibody IgG1 known as Herceptin ® has shown remarkable antitumor effects. Although this type of therapy has increased the cancer-free survival of patients, not all tumors respond to this treatment and cancers often develop resistance to the antibody. Despite the fact that Herceptin function has been extensively studied, the precise mechanism underlying its antitumor activity still remains incompletely defined. We previously demonstrated on human breast MCF-7 carcinoma and T-lymphoblastoid CEM cells that monoclonal antibody in combination with Lipoplex consisting of Lipofectamine mixed with plasmid DNA showed a more profound effect on cancer cell viability than antibody alone. The analyses of N-glycans isolated from cancer cells showed dramatic differences in profiles when cells were exposed to Herceptin. Moreover, the investigation of glycosylated peptides from the same cancer cell models after treatment revealed further alterations in the post-translational modifications. Tandem mass spectra obtained from the samples treated confirmed the presence of a series of glycopeptides bearing characteristic oligosaccharides as described in IgG1. However some of them differed by mass differences that corresponded to peptide backbones not described previously and more of them were detected from Herceptin treated samples than from cells transfected with Heceptin/Lipoplex. The results indicate that the presence of Lipoplex prevents antibody transformation and elongates its proper function. The better understanding of the multipart changes described in the glycoconjugates could provide new insights into the mechanism by which antibody induces regression in

In-depth research of multidrug resistance related cell surface glycoproteome in gastric cancer

“…Previously, we have found several proteins (PrP(C), p75(NTR), GAS1 and RhoE) that play important roles in MDR of gastric cancer, which unfortunately, are not sufficient enough to elucidate the development of MDR [11][12][13][14]. Recently, the correlation between drug resistance and change of glycoproteins has been reported in several papers [9,10,32,33]. But currently, there is no report concerning the relation between alteration of glycoproteins and MDR in Fig.…”

“…Recently, Di Michele et al screened the differential expressed glycoproteins between drug sensitive and resistant cell lines and found 4 glycoproteins remarkably upregulated in drug resistant cells as putative biomarkers for paclitaxel resistance in ovarian cancer [9]. Another study reported that treatment with molecule targeted drug herceptin could lead to dramatic differences of glycoproteins in breast cancer and T-lymphoblastoid cells [10]. But unfortunately, until now there is no study focusing on the correlation between the changes of glycoproteins and MDR in gastric cancer.…”

Characterization of site-specific glycosylation of secreted proteins associated with multi-drug resistance of gastric cancer

“…Intriguingly, recent researches indicated that glycomic alterations of glycoproteins exerted enormous effects on chemoresistance of cancers. Lattova et al verified the correlations between N-glycosylation variations and the efficacy of chemotherapies in breast cancer cells [ 23 , 24 ] and discovered that the emergence of galactosylated or biantennary fucosylated glycans might be associated with chemoresistance. Besides, Nakano et al observed that α 2–6 sialylation of N-glycans decreased with acquired resistance to desoxyepothilone B in leukemia cells [ 25 ].…”

An integrated approach to analyze EG2-hFc monoclonal antibody N-glycosylation by MALDI-MS

“…Phenylhydrazine (PHN) labelling was applied to enhance ionization of the glycans in the positive mode. 51 From Fig. 8A, it is observed that relative abundance ratios of neutral species remained unchanged (versus Fig.…”