Maackia Amurensis Seed Lectin (MASL) and soluble human podoplanin (shPDPN) Sequence Analysis and Effects on Human Oral Squamous Cell Carcinoma (OSCC) Cell Migration and Viability

Maackia amurensis lectins serve as research and botanical agents that bind to sialic residues on proteins. For example, M. amurensis seed lectin (MASL) targets the sialic acid modified podoplanin (PDPN) receptor to suppress arthritic chondrocyte inflammation, and inhibit tumor cell growth and motility. However, M. amurensis lectin nomenclature and composition are not clearly defined. Here, we sought to definitively characterize MASL and its effects on tumor cell behavior. We utilized SDS-PAGE and LC-MS/MS to find that M. amurensis lectins can be divided into two groups. MASL is a member of one group which is composed of subunits that form dimers, evidently mediated by a cysteine residue in the carboxy region of the protein. In contrast to MASL, members of the other group do not dimerize under nonreducing conditions. These data also indicate that MASL is composed of 4 isoforms with an identical amino acid sequence, but unique glycosylation sites. We also produced a novel recombinant soluble human PDPN receptor (shPDPN) with 17 threonine residues glycosylated with sialic acid moieties with potential to act as a ligand trap that inhibits OSCC cell growth and motility. In addition, we report here that MASL targets PDPN with very strong binding kinetics in the nanomolar range. Moreover, we confirm that MASL can inhibit the growth and motility of human oral squamous cell carcinoma (OSCC) cells that express the PDPN receptor. Taken together, these data characterize M. amurensis lectins into two major groups based on their intrinsic properties, clarify the composition of MASL and its subunit isoform sequence and glycosylation sites, define sialic acid modifications on the PDPN receptor and its ability to act as a ligand trap, quantitate MASL binding to PDPN with KD in the nanomolar range, and verify the ability of MASL to serve as a potential anticancer agent

Role of flexible laryngoscopy in evaluating aspiration.

Flexible fiberoptic laryngoscopy is used to evaluate dysphagia, but its clinical utility has not been compared to that of the videofluorographic swallowing study (VFSS). This study correlates parameters of both procedures and identifies laryngoscopic predictors of aspiration in 105 patients. Presence of aspiration, pharyngeal residue, laryngeal sensation, vocal cord mobility, and glottic closure during flexible laryngoscopy (FL), and gag reflex were correlated with aspiration during the VFSS. An algorithm for laryngoscopically detecting aspiration was synthesized. Aspiration (p = .004) and pharyngeal residue (p \u3c .00001) were highly correlated between the two studies. Aspiration during the VFSS was correlated with pharyngeal residue (p \u3c .00001) and laryngeal sensation (p = .027) during FL, but not glottic closure (p = .169) nor vocal cord mobility (p = .056). Patients with a normal gag reflex and without aspiration or pharyngeal residue during FL had a 2.94% risk of aspiration during the VFSS. Flexible laryngoscopy can be used as a relatively safe, portable screening test for aspiration, but cannot always replace the VFSS to identify the presence or cause of aspiration