Ki-67 labeling in postmitotic cells defines different Ki-67 pathways within the 2c compartment.
Simultaneous quantification of DNA and Ki-67 proliferation-associated antigen was performed using fluorescence image cytometry. In the MCF-7 cell line, the Ki-67 antigen content increases during the cell cycle, and its intranuclear distribution pattern varies. Quantitative evolution of Ki-67 content as a function of nuclear area makes it possible to define several pathways followed by cells going through the 2c compartment. 1) In some cells, the amount of Ki-67 antigen remains constant during G1 (Ki-67 stable pathway), and a characteristic speckled pattern can be observed. 2) In the larger fraction of cells analyzed, there is a postmitotic decrease in the Ki-67 (Ki-67 decrease pathway) content. In this pathway, labeling is located in the nucleoplasm in small nuclei, is located in nucleoli in intermediate-sized nuclei, and is absent from larger nuclei (G0). A progressive increase in Ki-67 content (Ki-67 increase pathway) was observed from intermediate-sized nuclei to S phase nuclei. From these results, we hypothesize that the Ki-67 stable pathway is the G1 phase of newly formed cells going directly to S phase in local optimal conditions of growth and that Ki-67 decrease pathway and Ki-67 increase pathway correspond to cells whose progression to S phase is regulated by extracellular factors.
Equipe de Reconnaissance des Fromes et Microscopie Quantitative, TIM3, U.S.R. CNRS B 00690, CERMO Université Joseph Fourier, Grenoble, France.
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S
du Manoir
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P
Guillaud
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E
Camus
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D
Seigneurin
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G
Brugal
D000818:Animals; D001943:Breast Neoplasms / Q000737:chemistry / Q000378:metabolism / Q000473:pathology*; D002453:Cell Cycle; D002460:Cell Line; D004273:DNA, Neoplasm / Q000032:analysis; D005260:Female; D005453:Fluorescence; D016193:G1 Phase; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry / Q000379:methods; D019394:Ki-67 Antigen; D008938:Mitosis; D009687:Nuclear Proteins / Q000378:metabolism*; D016196:S Phase
D004273:DNA, Neoplasm; D019394:Ki-67 Antigen; D009687:Nuclear Proteins