Quantitative analysis of β1,6GlcNAc-branched N-glycans on β4 integrin in cutaneous squamous cell carcinoma

Lectin-modified drug delivery systems - Recent applications in the oncology field

Chemotherapy with cytotoxic drugs remains the core treatment for cancer but, due to the difficulty to find general and usable biochemical differences between cancer cells and normal cells, many of these drugs are associated with lack of specificity, resulting in side effects and collateral cytotoxicity that impair patients' adherence to therapy. Novel cancer treatments in which the cytotoxic effect is maximized while adverse effects are reduced can be implemented by developing targeted therapies that exploit the specific features of cancer cells, such as the typical expression of aberrant glycans. Modification of drug delivery systems with lectins is one of the strategies to implement targeted chemotherapies, as lectins are able to specifically recognize and bind to cancer-associated glycans expressed at the surface of cancer cells, guiding the drug treatment towards these cells and not affecting healthy ones. In this paper, recent advances on the development of lectin-modified drug delivery systems for targeted cancer treatments are thoroughly reviewed, with a focus on their properties and performance in diverse applications, as well as their main advantages and limitations. The synthesis and analytical characterization of the cited lectin-modified drug delivery systems is also briefly described. A comparison with free-drug treatments and with antibody-modified drug delivery systems is presented, emphasizing the advantages of lectin-modified drug delivery systems. Main constraints and potential challenges of lectin-modified drug delivery systems, including key difficulties for clinical translation of these systems, and the required developments in this area, are also signalled.

FUT3 promotes gastric cancer cell migration by synthesizing Lea on ITGA6 and GLG1, affecting adhesion and vesicle distribution

AIMS

Lewis antigen plays an important role in the progression of gastric cancer (GC), FUT3 is a key enzyme in the synthesis of Lewis antigen, but the molecular mechanism of its promotion of GC progression remains unclear.

MAIN METHODS

We used Lea-antibody capturing coupled with mass spectrometry to identify the target proteins of FUT3, immunofluorescence (IF), molecular biology and cell function experiments were conducted to clarify the molecular mechanism of FUT3 promoting the migration and invasion of GC cells by regulating Lea glycosylation on ITGA6 and GLG1.

KEY FINDINGS

FUT3 promote migration and invasion of GC cells. FUT3 silencing in GC cells led to the aggregation of integrin α6β4 on the plasma membrane, associated with focal adhesion and hemidesmosome, and decreased GLG1 distribution in cellular vesicles. IGP analysis revealed Lea structure in 10 N-glycans of 2 glycosites for ITGA6 and 31 N-glycans of 4 glycosites for GLG1. Silencing ITGA6 promoted migration and invasion, while silencing GLG1 inhibited these processes in GC cells, regulated by FUT3-mediated Lea synthesis.

SIGNIFICANCE

In conclusion, FUT3's promotion of GC cell migration and invasion is attributed to Lea synthesis on ITGA6, impacting cell adhesion, and on GLG1, influencing distribution in intracellular vesicles. These findings may contribute to developing novel therapeutic targets for inhibiting or controlling the metastatic behavior of GC cells and enhancing our understanding of Lea's role in regulating protein functions.

Integrin α6β4 Confers Doxorubicin Resistance in Cancer Cells by Suppressing Caspase-3-Mediated Apoptosis: Involvement of N-Glycans on β4 Integrin Subunit

Drug resistance is a major obstacle to successful cancer treatment. Therefore, it is essential to understand the molecular mechanisms underlying drug resistance to develop successful therapeutic strategies. α6β4 integrin confers resistance to apoptosis and regulates the survival of cancer cells; however, it remains unclear whether α6β4 integrin is directly involved in chemoresistance. Here, we show that α6β4 integrin promotes doxorubicin resistance by decreasing caspase-3-mediated apoptosis. We found that the overexpression of α6β4 integrin by the β4 integrin gene rendered MDA-MB435S and Panc-1 cells more resistant to doxorubicin than control cells. The acquired resistance to doxorubicin by α6β4 integrin expression was abolished by the deletion of the cytoplasmic signal domain in β4 integrin. Similar results were found in MDA-MB435S and Panc-1 cells when N-glycan-defective β4 integrin mutants were overexpressed or bisecting GlcNAc residues were increased on β4 integrin by the co-expression of N-acetylglucosaminyltransferase III with β4 integrin. The abrogation of α6β4 integrin-mediated resistance to doxorubicin was accompanied by reduced cell viability and an increased caspase-3 activation. Taken together, our results clearly suggest that α6β4 integrin signaling plays a key role in the doxorubicin resistance of cancer cells, and N-glycans on β4 integrin are involved in the regulation of cancer cells.