Stimulation of plasminogen activator expression and induction of DNA synthesis by microtubule-disruptive drugs

Chou, Iih Nan; Zeiger, Joel; Solomon, James A.; Black, Paul H.

doi:10.1016/0006-291x(81)91584-9

Cited by 13 publications

(3 citation statements)

References 18 publications

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“…We have used taxol to evaluate the role of MT disassembly in initiating events associated with colchicine-induced cell activation. As shown in Tables 1 and 2, taxol (10 ,uM) alone had little or no effect on the levels of several total cellular nucleotide pools (ATP, UTP, or GTP) or (8). This indicates that a nearly complete cell activation can occur by cytoskeletal perturbation (MT depolymerization), despite the fact that these cells are unable to undergo mitosis under this condition.…”

Section: Resultsmentioning

confidence: 88%

“…The presence of 0.02% dimethyl sulfoxide (final concentration) in the medium had no effect on nucleotide pools or DNA synthesis. Numbers in parentheses represent % of labeled nuclei determined by autoradiography as described (8 (Table 4).…”

Section: Resultsmentioning

confidence: 99%

“…We have shown that treatment of quiescent 3T3 cells with colchicine or vinblastine alone, but not with cytochalasin B, results in cell activation as evidenced by stimulation of DNA synthesis and other criteria (8). Initiation of DNA synthesis by colchicine or vinblastine also occurs in chicken, mouse, and human fibroblasts (9,10).…”

mentioning

confidence: 91%

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Imbalance of total cellular nucleotide pools and mechanism of the colchicine-induced cell activation.

Chou¹,

Zeiger²,

Rapaport³

1984

Proc. Natl. Acad. Sci. U.S.A.

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Treatment with colchicine or vinblastine, both inhibitors of microtubule assembly, renders quiescent 3T3 cells in an "activated state" as evidenced by induction of DNA synthesis and other criteria. Microtubule disassembly caused by colchicine or vinblastine brings about a dramatic expansion of total cellular UTP pools with a concomitant diminution in total cellular ATP pools, thus resulting in a marked imbalance in total cellular nucleotide pools. Colchicine and vinblastine also stimulate total cellular RNA synthesis without enhancing uridine phosphorylation, suggesting that these drugs affect the G, phase of the cell cycle at a point beyond the enhancement of uridine phosphorylation that usually accompanies mitogenic stimulation of quiescent mammalian cells.The markedly expanded cellular UTP pools appear to be necessary for initiation of the colchicine-stimulated DNA synthesis because decreasing cellular UTP pools by addition of D-glucosamine results in a selective inhibition of DNA synthesis in the colchicine-stimulated, but not control, cells. Furthermore, Dglucosamine exerts its inhibitory effect only when it is present in the cultures within the first 14 hr after colchicine treatment. When added at 21 hr, D-glucosamine still decreases cellular UTP pools, but it is no longer inhibitory for DNA synthesis, which commences 14-16 hr after colchicine stimulation. Taxol, an antitumor drug, prevents microtubule disassembly and also blocks such events as expansion of total cellular UTP pools and stimulation of RNA and DNA synthesis, indicating that microtubule depolymerization acts as a primary event initiating the process of cell activation induced by colchicine.suggest that MT depolymerization is involved in modulating the initiation of DNA replication after mitogenic stimulation, although the underlying mechanism is not known.Since MT assembly in vitro is accompanied by GTP hydrolysis (12, 13), we have studied the effect of the colchicine-stimulated GO/G1 to S phase transition of 3T3 cells on the levels of cellular acid-soluble nucleotide pools, which have been shown to possess a regulatory role in the progression of mammalian cells along their cycle (14-17). We report here that MT disassembly induced by colchicine or vinblastine results in a sharp expansion of total cellular UTP pools with a concomitant diminution in total ATP pools and thus creates an imbalance in the cellular nucleotide pools as evidenced by large increases in the UTP/ATP ratio. In addition, we report that total cellular RNA synthesis, but not uridine phosphorylation, is stimulated following colchicine treatment. Furthermore, we also report that D-glucosamine effectively decreases the expanded cellular UTP pools and causes a selective inhibition of DNA synthesis in colchicinetreated, but not control, cells. Finally, we also report that taxol treatment effectively blocks events that normally occur following MT disassembly induced by colchicine or vinblastine. Taken together, our results suggest that the markedly increased cellular UTP p...

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Section: Resultsmentioning

confidence: 88%

Section: Resultsmentioning

confidence: 99%

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Imbalance of total cellular nucleotide pools and mechanism of the colchicine-induced cell activation.

Chou¹,

Zeiger²,

Rapaport³

1984

Proc. Natl. Acad. Sci. U.S.A.

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Perturbation of the actin cytoskeleton induces PAI-1 gene expression in cultured epithelial cells independent of substrate anchorage

Providence

Kutz

Higgins

1999

Cell Motil. Cytoskeleton

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Cell shape-dependent pathway of plasminogen activator inhibitor type-1 gene expression requires cytoskeletal reorganization

Hawks

Higgins

1998

J. Cell. Physiol.

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Synthesis of plasminogen activator inhibitor type-1 (PAI-1), a major physiological modulator of plasmin generation, is regulated by growth factors and changes in cell shape. To evaluate the specific relationship between PAI-1 gene expression and cytoarchitecture, serum-free cultures of quiescent rat kidney (NRK) cells were exposed to cytochalasin D (CD) at concentrations that disrupt microfilament structure. Treatment with 1-10 microM CD resulted in an increased 1) incidence of rounded cells, 2) relative PAI-1 mRNA content, and 3) fraction of PAI-1 protein-expressing cells. Abrupt increases in each response were evident at a final concentration of 5 microM CD. Maximal levels of induced PAI-1 transcripts (18-fold that of control) occurred 4 hours post-CD addition and declined thereafter but remained elevated (by at least tenfold) for 24 hours. Assessment of the metabolic requirements for CD-induced PAI-1 expression by using the protein synthesis inhibitors puromycin and cycloheximide indicated that PAI-1 transcripts were regulated in a complex manner in response to CD. The predominant mode of induction reflected secondary (protein synthesis-dependent) metabolic processes, although a minor, albeit significant, primary (protein synthesis-independent) pathway was also evident. PAI-1 mRNA levels in NRK cells maintained in serum- and CD-free agarose suspension culture were low or undetectable. Relative abundance of PAI-1 transcripts in suspended cells cultured in the presence of CD, however, closely approximated that of plastic-adherent, CD-treated cells (13-fold over control). NRK cells in suspension culture with or without CD were morphologically identical, remaining spherical and unattached. It appears, therefore, that cell rounding alone is not a sufficient stimulus to induce PAI-1 expression in quiescent NRK cells and that perturbation of the actin skeleton as a consequence of CD treatment is a critical event in the inductive response. A protein tyrosine kinase is likely involved in the CD-mediated signal-transduction cascade, since induced PAI-1 expression can be down-regulated by genistein and herbimycin A but not by calphostin C or tyrphostin B46.

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Stimulation of plasminogen activator expression and induction of DNA synthesis by microtubule-disruptive drugs

Cited by 13 publications

References 18 publications

Imbalance of total cellular nucleotide pools and mechanism of the colchicine-induced cell activation.

Imbalance of total cellular nucleotide pools and mechanism of the colchicine-induced cell activation.

Perturbation of the actin cytoskeleton induces PAI-1 gene expression in cultured epithelial cells independent of substrate anchorage

Cell shape-dependent pathway of plasminogen activator inhibitor type-1 gene expression requires cytoskeletal reorganization

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