This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Rao, J. Y. Articles by Hemstreet, G. P. Search for Related Content PubMed PubMed Citation Articles by Rao, J. Y. Articles by Hemstreet, G. P., III

Cellular F-Actin Levels as a Marker for Cellular Transformation: Relationship to Cell Division and Differentiation¹

Departments of Urology [J.Y.R., R.E.H., P.L.J., R.A.B., G.P.H.], Pathology [G.P.H.], Biochemistry [R.E.H.], and Environmental Health [R.E.H., G.P.H.], University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73190; Flow Cytometry Laboratory, Department of Pathology, Veterans Administration Medical Center, Oklahoma City, Oklahoma 73104 [W. D. B., L. T. A.]; and Department of Zoology, University of Oklahoma, Norman, Oklahoma 73019 [P. B. B.]

Transformation is associated with profound structural and quantitative changes in the cytoskeleton. Herein we report studies using F-actin, a major cytoskeletal protein, as a quantitative marker for transformation cells, focusing on separating the effects of the cell cycle, cell differentiation, and transformation. The model system for these studies consisted of three lymphoblastic cell lines, one untransformed line (RPMI) and two transformed lines, one (HL-60) of which can be induced to differentiate and the other (Daudi) which cannot. The relation of F-actin levels to cell cycle was studied by flow cytometry with the use of fluorescein-phalloidin to label F-actin and propidium iodide to label DNA. F-Actin levels in transformed Daudi and HL-60 lines were only two-thirds that of the untransformed RPMI cells. Histograms of the distribution of F-actin showed that the transformed lines consisted of two cell populations, one having an F-actin content near that of untransformed cells and the other having much less. Cell cycle analysis showed that F-actin in untransformed cells increased 10–15% as cells entered the S compartment, remaining approximately constant through G₂ + M phases of the cell cycle, but in transformed cells the major increase in F-actin occurred during G₂ + M phase. Double-label studies with rhodamine-phalloidin for F-actin and KI-67 monoclonal antibody for dividing cells (cells at late G₁,S,G₂, and M) measured with quantitative fluorescence image analysis showed that the mean F-actin content of dividing cells was twice that of nondividing cells. These results suggested that most of the cell division-related F-actin increase occurred during late G₁ phase in untransformed cells. Differentiation of HL-60 cells with dimethyl sulfoxide or retinoic acid normalized the F-actin content of the nondividing cell population, but dimethyl sulfoxide and retinoic acid produced no detectable change in F-actin in the undifferentiable Daudi cells. A tumor promoter (12-O-tetradecanoylphorphol-13-acetate) inhibits differentiation of hematopoietic cells, resulted in a 32% decrease in the mean F-actin content of RPMI cells due to the appearance of a new subpopulation of low F-actin content. The 12-O-tetradecanoylphorbol-13-acetate-induced changes reversed slowly after removal of 12-O-tetradecanoylphorbol-13-acetate but more rapidly in the presence of retinoic acid. These results indicate that F-actin quantification can serve as a marker for cellular transformation and provides a tool for studying the mechanisms of cellular differentiation that may lead to a better understanding of the oncogenic process.

¹ This work was supported, in part, by a subcontract from the Cancer Institute of the Chinese Academy of Medical Sciences, Beijing, People's Republic of China, for "Quantitative Fluorescence Image Analysis (QFIA) of Esophageal Samples to Detect Abnormal Levels of Nuclear Nucleic Acid," as a part of a National Cancer Institute-sponsored "Study of the Effect of Nutritional Intervention on Intermediate Endpoints of Esophageal Cancer in Linxian, China"; by a Postdoctoral Research Fellowship awarded to J.Y.R. by the Graduate College of the University of Oklahoma Health Sciences Center; and in part by the Veterans Administration and CDC/National Institute of Occupation Safety and Health Grant R01-OH02647.

² To whom requests for reprints should be addressed, at Department of Urology, Oklahoma University Health Sciences Center, P.O. Box 26901, Oklahoma City, OK 73190.

Received 9/25/89. Revised 12/19/89.

This article has been cited by other articles:

				Q.-Y. Lu, Y.-S. Jin, A. Pantuck, Z.-F. Zhang, D. Heber, A. Belldegrun, M. Brooks, R. Figlin, and J. Rao Green Tea Extract Modulates Actin Remodeling via Rho Activity in an In vitro Multistep Carcinogenic Model Clin. Cancer Res., February 15, 2005; 11(4): 1675 - 1683. [Abstract] [Full Text] [PDF]

				C. Odaka, M. L. Sanders, and P. Crews Jasplakinolide Induces Apoptosis in Various Transformed Cell Lines by a Caspase-3-Like Protease-Dependent Pathway Clin. Vaccine Immunol., November 1, 2000; 7(6): 947 - 952. [Abstract] [Full Text] [PDF]

				I. Fabian, D. Halperin, S. Lefter, L. Mittelman, R. T. Altstock, O. Seaon, and I. Tsarfaty Alteration of Actin Organization by Jaspamide Inhibits Ruffling, but not Phagocytosis or Oxidative Burst, in HL-60 Cells and Human Monocytes Blood, June 1, 1999; 93(11): 3994 - 4005. [Abstract] [Full Text] [PDF]

				A. W. Heldman, D. E. Kandzari, R. W. Tucker, L. E. Crawford, E. R. Fearon, K. S. Koblan, and P. J. Goldschmidt-Clermont EJ-Ras Inhibits Phospholipase C{gamma}1 but Not Actin Polymerization Induced by Platelet-Derived Growth Factor-BB via Phosphatidylinositol 3-Kinase Circ. Res., February 1, 1996; 78(2): 312 - 321. [Abstract] [Full Text]