Intramitochondrial bodies in a human cell line carrying oncornavirus-like particles

Area of Science:

• Cell Biology
• Virology
• Oncology

Background:

• Mitochondria play crucial roles in cellular energy production and are implicated in various diseases, including cancer.
• Viral infections can alter cellular structures, including mitochondria, impacting cell function and potentially contributing to oncogenesis.

Purpose of the Study:

• To investigate the presence and morphology of electron-dense particles within mitochondria of cancer cells.
• To compare these particles with those observed in virus-infected cells.

Main Methods:

• Electron microscopy was used to examine mitochondria in transformed mouse fibroblasts and human amnion cells infected with human mammary carcinoma cell culture supernatants.
• Morphological analysis focused on identifying and characterizing electron-dense particles within the mitochondrial matrix.

Main Results:

• Electron-dense particles, 80-100 nm in diameter, were identified in the mitochondria of both transformed mouse fibroblasts and human amnion cells.
• These intramitochondrial particles were more abundant in human cell cultures during the early stages after subculture.
• The observed particles exhibited morphological similarities to those previously reported in mitochondria of cells infected with Rous sarcoma virus.

Conclusions:

• The presence of specific electron-dense particles in cancer cell mitochondria suggests a potential role or association with the transformed state.
• Morphological similarities to particles in Rous sarcoma virus-infected cells may indicate a common viral or oncogenic mechanism affecting mitochondria.