Morphological characterization of cardiomyocytes isolated from a transplantable cardiac tumor derived from transgenic mouse atria (AT-1 cells).
We have developed a transplantable tumor lineage derived from transgenic mouse atrial cardiomyocytes that express the SV40 large T oncogene and have named these cardiomyocytes AT-1 cells. In this study, the transplantable tumors, freshly isolated tumor cardiomyocytes, and cultured tumor cardiomyocytes were examined using phase-contrast microscopy, autoradiography, and electron microscopy. The vast majority of the subcutaneous tumor cells, greater than 90% of the cellular mass of the tumor, exhibited sarcomeric banding. Ultrastructural characteristics typical of in vivo atrial cardiac muscle cells, including well-organized myofibrils, gap junctions, and atrial-specific cytoplasmic granules, were observed in in situ and in freshly isolated AT-1 cells. Those cells that did not contain some form of organized myofibrils were primarily vascular elements, such as endothelial cells. Labeling with [3H]thymidine indicated that greater than 90% of cultured AT-1 cells were synthesizing DNA; furthermore, many cells could be seen undergoing cell division. Electron microscopy revealed that the cultured AT-1 cardiomyocytes contained all of the above-described characteristics, including a well-developed transverse tubular system.
Delcarpio
J B
JB
Department of Anatomy, Louisiana State University Medical Center, New Orleans 70112.
Lanson
N A
NA
Field
L J
LJ
Claycomb
W C
WC
D000818:Animals; D002454:Cell Differentiation; D002455:Cell Division; D006338:Heart Neoplasms / Q000473:pathology* / Q000648:ultrastructure; D051379:Mice; D008822:Mice, Transgenic; D008854:Microscopy, Electron; D008938:Mitosis; D009210:Myofibrils / Q000648:ultrastructure; D009368:Neoplasm Transplantation; D014407:Tumor Cells, Cultured