Tive control for Tn antigen expression. c Expression of Tn antigen and aberrant O-glycans in COSMC knockdown cells. Western blot analysis showed a strong expression of aberrant O-glycans as well as Tn antigen in Panc-1 COSMC knockdown cells compared to control cells. Sialyl-Tn and Tn antibodies were used as well as lectins such as VVL (Vicia villosa lectin) and WFL (Wisteria floribunda lectin)vector (Additional file 1: Figure S4). Additionally, down regulation of COSMC was confirmed on mRNA level by real-time PCR, achieving 97 efficiency in Panc-1 and 73 in L3.6pl cells (Fig. 2b and d). Next, expression of atypical O-glycans was evaluated using different glyco epitope recognizing antibodies and lectins. Using sialyl-Tn and Tn antigen antibodies as well as VVL and WFL, revealed an enhancement of distinct staining patterns in COSMC knockdown cells compared to control cells (Fig. 1c). L3.6pl cells revealed an enhanced Tn antigen expression only after treatment with Neuraminidase (Additional file 1: Figure S5). Immunocytochemistry revealed PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/15501003 an enhanced staining of VVL and WFL lectin in COSMC knockdown cells compared to controls (Additional file 1: Figure S6).Decreased expression of GalNAc-transferases in COSMC knockdown cells(p Capecitabine cells. The GalNAc-T isoforms 1, 2, 7, 10, 11, 12, and 18 were expressed in Panc-1 cells (Fig. 2a). Interestingly, COSMC-depleted Panc-1 cells showed a substantial decrease in mRNA expression for all detected GalNAc-T isoforms, compared to the respective control cells. In fac.