Human PDPN blocking peptide

Cancer-initiating cell (CIC) hypothesis suggests that CICs may be responsible for the generation of tumors that recapitulate the histology of the primary tumor at distant sites. We investigated the distribution of CIC markers (podoplanin (PDPN), CD44, and p63) positive cells of lung squamous cell carcinoma (SqCC) within primary and matched lymph node (LN) metastatic tumors to confirm this hypothesis (n = 113). In 61 cases, the PDPN-positive cells were localized in more peripheral areas of the tumor nests than the CD44- and p63-positive cells. This distribution pattern corresponded to a hierarchical distribution (HD)' reported previously. Among the cases with HD-(+) primary tumors (n = 61), the number showing HD-(+) LN metastatic tumors was 31 (51%), while among the cases with HD-() primary tumors (n = 52), the number showing HD-(+) LN metastatic tumors was 7 (13%) (p<0.01). Primary and matched pulmonary metastatic (PM) tumors were also analyzed (n = 31), and a significant relationship of the HD pattern between them was also detected (p = 0.01). These results indicate that PDPN-positive cells might reflect the most immature cells in the differentiation process of metastatic SqCC and might generate metastatic tumors that recapitulate the histologic heterogeneity of the primary tumor.

Objective Synovial membrane inflammation is common in osteoarthritis (OA) and increases cartilage injury. However, synovial fluid and histology studies suggest that OA inflammatory responses are not homogeneous. Greater understanding of these responses may provide new insights into OA disease mechanisms. We undertook this study to develop a novel multiparameter approach to phenotype synovial responses in knee OA. Methods Cell composition and soluble protein production were measured by flow cytometry and multiplex enzyme-linked immunosorbent assay in synovium collected from OA patients undergoing knee replacement surgery (n = 35). Results Testing disaggregation conditions showed that aggressive digestion improved synovial cell yield and mesenchymal staining by flow cytometry, but it negatively impacted CD4+ T cell and CD56+ natural killer cell staining. Less aggressive digestion preserved these markers and showed highly variable T cell infiltration (range 0-43%; n = 32). Correlation analysis identified mesenchymal subpopulations associated with different nonmesenchymal populations, including macrophages and T cells (CD45+CD11b+HLA-DR+ myeloid cells with PDPN+CD73+CD90-CD34- mesenchymal cells [r = 0.65, P < 0.0001]; and CD45+CD3+ T cells with PDPN+CD73+CD90+CD34+ mesenchymal cells [r = 0.50, P = 0.003]). Interleukin-6 (IL-6) measured by flow cytometry strongly correlated with IL-6 released by ex vivo culture of synovial tissue (r = 0.59, P = 0.0012) and was highest in mesenchymal cells coexpressing CD90 and CD34. IL-6, IL-8, complement factor D, and IL-10 release correlated positively with tissue cellularity (P = 0.0042, P = 0.018, P = 0.0012, and P = 0.038, respectively). Additionally, increased CD8+ T cell numbers correlated with retinol binding protein 4 (P = 0.033). Finally, combining flow cytometry and multiplex data identified patient clusters with different types of inflammatory responses. Conclusion We used a novel approach to analyze OA synovium, identifying patient-specific inflammatory clusters. Our findings indicate that phenotyping synovial inflammation may provide new insights into OA patient heterogeneity and biomarker development.