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Molecular mechanism of TGF-beta1-induced apoptosis in HC11 mouse mammary epithelial cells (MEC).
Cell Mol Biol (Noisy-le-grand) 2001; 47 Online Pub:OL197-208CM

Abstract

The involvement of p53, Bax, cytochrome C and CPP-32 (caspase-3) in the molecular mechanism ofTGF-beta1-induced apoptosis in HC11 mouse mammary epithelial cells (MEC) was examined. Laser scanning cytometry (LSC) was applied for the quantitative analysis of expression and distribution of examined apoptosis-related proteins in the cytoplasmic (Cf) and nuclear (Nf) area. Maximal pixel of fluorescence (MP) parameter corresponding to aggregation of molecules in the cell was also measured. Confocal and immunoelectron microscopy were used as a complementary methods. Apoptosis induced by TGF-beta1 (2 ng/ml) was associated with the increase of Bax MP observed within 60 min. after cytokine administration, indicating aggregation of Bax in the cell. Immunoelectron microscopy revealed Bax aggregation on mitochondrial membranes, rough endoplasmic reticulum, Golgi apparatus, cytoskeleton, nuclear envelope and inside of nucleus. The accumulation of Bax in the nucleus was confirmed by compartmental Bax analysis, showing the increase of cell number with elevated Bax Nf in 2 hr after TGF-beta1 administration to the culture. The redistribution of Bax within the cell was dependent on its activation occurring by the cleavage at N-terminal epitope and exposure of BH3 domain. Bax aggregation on organelles was completely abolished by prolactin or IGF-I. TGF-beta1 increased p53 MP, evidently after 4 hr of cell culture exposure to this cytokine. p53 was accumulated first of all in the nucleus, which was shown by significant increase of p53 Nf/Cf ratio and increase of p53-related nuclear fluorescence on confocal images. TGF-beta1 decreased cytochrome C MP, which corresponded to its release from mitochondria and dissipation in the cytosol. It was accompanied by the increase of CPP-32 MP and concentration of 89 kDa product of PARP degradation in the nucleus. In conclusion, TGF-beta1 triggers apoptosis in MEC through mitochondrial pathway involving: activation and translocation of Bax to mitochondrial membranes, release of cytochrome C from mitochondria, activation of CPP-32 and degradation of its substrate - PARP in the nucleus. Activation and subcellular redistribution of Bax is inhibited by lactogenic hormones: prolactin and IGF-I.

Authors+Show Affiliations

Dept. of Physiology, Biochemistry, Pharmacology and Toxicology, Faculty of Veterinary Medicine, Warsaw Agricultural University, Poland.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

11936868

Citation

Kolek, O, et al. "Molecular Mechanism of TGF-beta1-induced Apoptosis in HC11 Mouse Mammary Epithelial Cells (MEC)." Cellular and Molecular Biology (Noisy-le-Grand, France), vol. 47 Online Pub, 2001, pp. OL197-208.
Kolek O, Gajkowska B, Godlewski MM, et al. Molecular mechanism of TGF-beta1-induced apoptosis in HC11 mouse mammary epithelial cells (MEC). Cell Mol Biol (Noisy-le-grand). 2001;47 Online Pub:OL197-208.
Kolek, O., Gajkowska, B., Godlewski, M. M., & Motyl, T. (2001). Molecular mechanism of TGF-beta1-induced apoptosis in HC11 mouse mammary epithelial cells (MEC). Cellular and Molecular Biology (Noisy-le-Grand, France), 47 Online Pub, pp. OL197-208.
Kolek O, et al. Molecular Mechanism of TGF-beta1-induced Apoptosis in HC11 Mouse Mammary Epithelial Cells (MEC). Cell Mol Biol (Noisy-le-grand). 2001;47 Online Pub:OL197-208. PubMed PMID: 11936868.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Molecular mechanism of TGF-beta1-induced apoptosis in HC11 mouse mammary epithelial cells (MEC). AU - Kolek,O, AU - Gajkowska,B, AU - Godlewski,M M, AU - Motyl,T, PY - 2002/4/9/pubmed PY - 2002/10/9/medline PY - 2002/4/9/entrez SP - OL197 EP - 208 JF - Cellular and molecular biology (Noisy-le-Grand, France) JO - Cell. Mol. Biol. (Noisy-le-grand) VL - 47 Online Pub N2 - The involvement of p53, Bax, cytochrome C and CPP-32 (caspase-3) in the molecular mechanism ofTGF-beta1-induced apoptosis in HC11 mouse mammary epithelial cells (MEC) was examined. Laser scanning cytometry (LSC) was applied for the quantitative analysis of expression and distribution of examined apoptosis-related proteins in the cytoplasmic (Cf) and nuclear (Nf) area. Maximal pixel of fluorescence (MP) parameter corresponding to aggregation of molecules in the cell was also measured. Confocal and immunoelectron microscopy were used as a complementary methods. Apoptosis induced by TGF-beta1 (2 ng/ml) was associated with the increase of Bax MP observed within 60 min. after cytokine administration, indicating aggregation of Bax in the cell. Immunoelectron microscopy revealed Bax aggregation on mitochondrial membranes, rough endoplasmic reticulum, Golgi apparatus, cytoskeleton, nuclear envelope and inside of nucleus. The accumulation of Bax in the nucleus was confirmed by compartmental Bax analysis, showing the increase of cell number with elevated Bax Nf in 2 hr after TGF-beta1 administration to the culture. The redistribution of Bax within the cell was dependent on its activation occurring by the cleavage at N-terminal epitope and exposure of BH3 domain. Bax aggregation on organelles was completely abolished by prolactin or IGF-I. TGF-beta1 increased p53 MP, evidently after 4 hr of cell culture exposure to this cytokine. p53 was accumulated first of all in the nucleus, which was shown by significant increase of p53 Nf/Cf ratio and increase of p53-related nuclear fluorescence on confocal images. TGF-beta1 decreased cytochrome C MP, which corresponded to its release from mitochondria and dissipation in the cytosol. It was accompanied by the increase of CPP-32 MP and concentration of 89 kDa product of PARP degradation in the nucleus. In conclusion, TGF-beta1 triggers apoptosis in MEC through mitochondrial pathway involving: activation and translocation of Bax to mitochondrial membranes, release of cytochrome C from mitochondria, activation of CPP-32 and degradation of its substrate - PARP in the nucleus. Activation and subcellular redistribution of Bax is inhibited by lactogenic hormones: prolactin and IGF-I. SN - 0145-5680 UR - https://www.unboundmedicine.com/medline/citation/11936868/Molecular_mechanism_of_TGF_beta1_induced_apoptosis_in_HC11_mouse_mammary_epithelial_cells__MEC__ DB - PRIME DP - Unbound Medicine ER -