PMC

In vivo passage of xenografts generated with human mucoepidermoid carcinoma cell lines. UM-HMC-3A or UM-HMC-3B (100,000 cells/scaffold) were transplanted into immunodeficient mice. When tumors reached an average volume of 1,000 mm³, they were retrieved and digested, single cell suspensions were prepared, and 100,000 unsorted cells were seeded in new biodegradable scaffolds and passaged into new mice. (A,B) Graphs depicting growth of xenograft tumors generated with UM-HMC-3A (A) or UM-HMC-3B (B) cells over 4 in vivo passages.

UM-HMC cells generate xenograft tumors when implanted in immunodeficient mice. (A) Macroscopic view of a typical specimen of human mucoepidermoid carcinoma immediately after surgical removal (Top, left panel). Macroscopic view of xenografts generated upon transplantation of UM-HMC into immunodeficient mice (Top, right panel). And macroscopic view of xenograft tumors (bilateral) growing in the subcutaneous space of immunodeficient mice (bottom panel). (B) Graph depicting time to tumor palpability. Palpable tumors were defined as those surpassing the size of the biodegradable scaffold used to transplant UM-HMC-3A (n=8), UM-HMC-3B (n=6), or UM-HMC-2 (n=8). (C) Photomicrographs of histological sections (HE) obtained from xenograft tumors generated by the transplantation of UM-HMC-3A cells into immunodeficient mice. The boxes in the low magnification (40×) image depict the areas were the high magnification images (200×) were obtained from, i.e. red box (mucous-like cells) and black box (epidermoid-like cells).

Xenografts generated with human mucoepidermoid carcinoma cell lines retain their histopathology over in vivo passages. UM-HMC-3A or UM-HMC-3B (100,000 cells/scaffold) were transplanted into immunodeficient mice. When tumors reached an average volume of 1,000 mm³, they were retrieved and digested, single cell suspensions were prepared, and 100,000 unsorted cells were seeded in new biodegradable scaffolds to passage them to new mice. Photomicrographs of histological sections (Hematoxilin/eosin) of the human tumor specimen from which the respective cell lines were generated, 1^st and 2^nd passages in mice. In each panel the left-side image is at low magnification (40×), the top right-side image depicts an area of predominance of epidermoid-like cells and the bottom right-side image depicts an area of mucous-like cells. Scale bars represent 50 μm.

Human mucoepidermoid carcinomas and UM-HMC-derived xenografts secrete high levels of mucopolysaccharides. (A) Photomicrographs of histological sections stained with Periodic acid Schiff (PAS) of representative fields from the human tumors that generated the cell lines, as well as 1^st and 2^nd passage UM-HMC-3A and UM-HMC-3B-derived xenografts. In each panel the left-side image is at low magnification (40×), the top right-side image depicts an area of predominance of epidermoid-like cells and the bottom right-side image depicts an area of mucous-like cells. Scale bars represent 50 μm. (B) Photomicrographs depicting the similar PAS patterns in the human mucoepidermoid carcinoma surgical specimen and in the 2^nd passage xenograft generated with the UM-HMC cell line derived from this specimen (200×). Black arrows point to PAS-positive globules in the human tumor and in the mouse xenograft.

Characterization of human mucoepidermoid carcinoma cell lines derived from a local recurrence (UM-HMC-3A) and a metastatic lymph node (UM-HMC-3B). (A) Photomicrographs of UM-HMC3A and UM-HMC-3B cells cultured for 100 passages in vitro. Magnification at 100× (left columns) and 200× (right columns). (B) RT-PCR for screening of a panel of human mucoepidermoid carcinoma cell lines for the Crtc1-Maml2 fusion oncogene (196 bp). The head and neck squamous cell carcinoma cell line (UM-SCC-74B) was used as a negative control. (C) Western blot analysis of CRTC1 and its prototypic target NR4A2 in human mucoepidermoid carcinoma cell lines. The adenoid cystic carcinoma cell line (ACC-52) and the human embryonic kidney cell line (293T) were used as controls. (D) Western blot analysis of epithelial markers (EGFR, E-Cadherin, Pan-cytokeratin, Cytokeratin-7) and a mesenchymal marker (Vimentin) in human mucoepidermoid carcinoma cell lines. The benign human pleomorphic adenoma (UM-HPA-1) cell line was used as control for this experiment.