scholarly journals Growth control in cultured 3T3 fibroblasts II. Molecular properties of a fraction enriched in growth inhibitory activity.

1982 ◽  
Vol 92 (2) ◽  
pp. 523-530 ◽  
Author(s):  
P A Steck ◽  
J Blenis ◽  
P G Voss ◽  
J L Wang

Treatment of sparse, proliferating cultures of 3T3 cells with medium conditioned by exposure to density-inhibited 3T3 cultures resulted in an inhibition of growth and division in the target cells when compared to similar treatment with unconditioned medium. This growth inhibitory activity was fractionated by ammonium sulfate precipitation and gel filtration, yielding one fraction that was 35-fold enriched in specific activity. Analysis of the chemical and biological properties of this highly active fraction indicated that: (a) it is an endogenous cell product, synthesized by the 3T3 cells and shed into the medium; (b) it is a protein and its activity is sensitive to treatment with pronase; (c) the constituent polypeptide chains have molecular weights of 10,000 and 13,000; and (d) it is not cytotoxic and its effect on target cells are reversible. These results suggest that we have partially purified from conditioned medium an endogenous growth regulatory factor that may play a role in density-dependent inhibition of growth in cultured fibroblasts. We propose the term Fibroblast Growth Regulator to describe this class of molecules.

In an extended investigation of the growth-inhibitory activity of carcinogenic compounds and related substances, over two hundred compounds were tested, including various 5-, 10- and 9 : 10-substituted benzanthracenes, dimethyl derivatives of anthracene, nitrogenous analogues of 1 : 2-benzanthracene, benzphenothiazines and dibenzphenothiazines, compounds related to 3 : 4-benzphenanthrene, dibenzfluorenes, dibenzcarbazoles, dibenzpyrenes, azonaphthalenes and related products, naphthylam ines and naphthaquinones, arsenonaphthalenes, derivatives of triphenylethylene, and diphenyl derivatives of indene, β -naphthindole and β -naphthofuran. A striking degree of correspondence was often shown by the inhibitory and carcinogenic activity of closely related com pounds (e. g. 5-alkyl benzanthracenes; dibenzfluorenes; dibenzphenanthrenes; 2 : 2'-azonaphthalene, 2 : 2'-diamino -1 : 1'-dinaphthyl and 3 : 4 : 5 : 6-dibenzcarbazole). However, no inhibitory activity was observed for certain carcinogenic 10- and 9 : 10- substituted benzanthracenes. On the other hand, inhibitory activity was noted in a few compounds (e. g. 1 : 2'-azonaphthalene) which have yielded few or no tum ours in exhaustive tests, and in some of a group of synthetic oestrogenic compounds which, although not carcinogenic in the usual sense, are nevertheless associated with the induction of individual types of tum our under special conditions. The relation between molecular structure and inhibitory activity depends in general upon an optimal degree of molecular complexity and upon certain more specific requirements. Nevertheless, the results obtained with derivatives of triphenylethylene suggest that inhibitory activity may still be shown by compounds diverging widely from the polycyclic structure and possessing only a skeletal resemblance. Diminution of inhibitory effect with increased substituent size was shown in the 5-alkyl benzanthracenes tested, although the same relation does not necessarily obtain for other positions. The influence of the nature of the substituent is seen (for example) in the contrast between 10-methyl-, 10-amino- and 10-cyano-l: 2-benzanthracene (inhibitory) and 10-isopropyl - 1:2-benzanthracene (inactive). Lastly, numerous experiments indicated that solubilization of an active compound usually entails decrease of activity, although certain apparent exceptions were encountered. In addition to the relationship between inhibitory activity and carcinogenicity, and that between both biological properties and chemical structure, consideration is also given to the mode of production of the inhibitory effect.


1979 ◽  
Vol 83 (3) ◽  
pp. 562-575 ◽  
Author(s):  
P A Steck ◽  
P G Voss ◽  
J L Wang

Treatment of sparse, proliferating cultures of 3T3 cells (target cells) with medium conditioned by exposure to density-inhibited 3T3 cultures resulted in an inhibition of growth and division in the target cells when compared to similar treatment with unconditioned medium (UCM). This differential effect of conditioned medium (CM) and UCM on target cells was demonstrated using three assay systems: (a) assessment of total cell number; (b) measurement of [3H]thymidine incorporated into acid-precipitable DNA; and (c) determination of the percentage of radioactively labeled nuclei in individual cells after incorporation of [3H]thymidine. The difference in the total incorporation of [3H]thymidine in CM-treated and UCM-treated cells was reflected by a difference in the percent of labeled cells. There was no differences in the average number of grains per labeled cell in the two cultures. Moreover, the inhibitory effect of the CM on target cell proliferation was reversible. Finally, this growth inhibitory activity can be collected in serum-free medium, precipitated by ammonium sulfate, and fractionated by gel filtration. In these purification procedures, the inhibitory activity was consistently found to be associated with the protein-containing fractions of the CM. No activity was found upon similar treatment with UCM. These results suggest that a system has been developed for the purification and molecular analysis of growth inhibitory factors that may mediate growth control in culture fibroblasts.


2021 ◽  
Vol 14 (1) ◽  
pp. 49
Author(s):  
David Méndez-Luna ◽  
Loreley Araceli Morelos-Garnica ◽  
Juan Benjamín García-Vázquez ◽  
Martiniano Bello ◽  
Itzia Irene Padilla-Martínez ◽  
...  

The implementation of chemo- and bioinformatics tools is a crucial step in the design of structure-based drugs, enabling the identification of more specific and effective molecules against cancer without side effects. In this study, three new compounds were designed and synthesized with suitable absorption, distribution, metabolism, excretion and toxicity (ADME-tox) properties and high affinity for the G protein-coupled estrogen receptor (GPER) binding site by in silico methods, which correlated with the growth inhibitory activity tested in a cluster of cancer cell lines. Docking and molecular dynamics (MD) simulations accompanied by a molecular mechanics/generalized Born surface area (MMGBSA) approach yielded the binding modes and energetic features of the proposed compounds on GPER. These in silico studies showed that the compounds reached the GPER binding site, establishing interactions with a phenylalanine cluster (F206, F208 and F278) required for GPER molecular recognition of its agonist and antagonist ligands. Finally, a 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyltetrazolium bromide (MTT) assay showed growth inhibitory activity of compounds 4, 5 and 7 in three different cancer cell lines—MIA Paca-2, RCC4-VA and Hep G2—at micromolar concentrations. These new molecules with specific chemical modifications of the GPER pharmacophore open up the possibility of generating new compounds capable of reaching the GPER binding site with potential growth inhibitory activities against nonconventional GPER cell models.


2021 ◽  
pp. 096032712110214
Author(s):  
JY Lee ◽  
HM Lim ◽  
CM Lee ◽  
S-H Park ◽  
MJ Nam

Indole-3-carbinol (I3C) is a phytochemical that exhibits growth-inhibitory activity against various cancer cells. However, there are limited studies on the effects of I3C on colon cancer cells. In this study, the growth-inhibitory activity of I3C against the human colorectal carcinoma cell line (LoVo) was examined. The results of the 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide, colony formation, and cell counting assays revealed that I3C suppressed the proliferation of LoVo cells. Microscopy and wound-healing analyses revealed that I3C affected the morphology and inhibited the migration of LoVo cells, respectively. I3C induced apoptosis and DNA fragmentation as evidenced by the results of fluorescein isothiocyanate-conjugated annexin V staining and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling assay, respectively. Additionally, I3C arrested the cell cycle at the G0/G1 phase and enhanced the reactive oxygen species levels. Western blotting analysis revealed that treatment with I3C resulted in the activation of apoptotic proteins, such as poly(ADP-ribose) polymerase, caspase-3, caspase-7, caspase-9, Bax, Bim, and p53 in LoVo cells. These results indicate that I3C induces apoptosis in LoVo cells by upregulating p53, leading to the activation of Bax and caspases. Taken together, I3C exerts cytotoxic effects on LoVo cells by activating apoptosis.


1989 ◽  
Vol 264 (3) ◽  
pp. 1534-1542
Author(s):  
T C Wright ◽  
J J Castellot ◽  
M Petitou ◽  
J C Lormeau ◽  
J Choay ◽  
...  

Development ◽  
1991 ◽  
Vol 112 (1) ◽  
pp. 33-42
Author(s):  
P.A. Eccleston ◽  
R. Mirsky ◽  
K.R. Jessen

In the developing peripheral nerve, Schwann cells proliferate rapidly and then become quiescent, an essential step in control of Schwann cell differentiation. Cell proliferation is controlled by growth factors that can exert positive or inhibitory influences on DNA synthesis. It has been well established that neonatal Schwann cells divide very slowly in culture when separated from neurons but here we show that when culture was continued for several months some cells began to proliferate rapidly and non-clonal lines of immortalised Schwann cells were established which could be passaged for over two years. These cells had a similar molecular phenotype to short-term cultured Schwann cells, except that they expressed intracellular and cell surface fibronectin. The difference in proliferation rates between short- and long-term cultured Schwann cells appeared to be due in part to the secretion by short-term cultured Schwann cells of growth inhibitory activity since DNA synthesis of long-term, immortalised Schwann cells was inhibited by conditioned medium from short-term cultures. This conditioned medium also inhibited DNA synthesis in short-term Schwann cells stimulated to divide by glial growth factor or elevation of intracellular cAMP. The growth inhibitory activity was not detected in the medium of long-term immortalised Schwann cells, epineurial fibroblasts, a Schwannoma (33B), astrocytes or a fibroblast-like cell-line (3T3) and it did not inhibit serum-induced DNA synthesis in epineurial fibroblasts, 33B cells or 3T3 cells. The activity was apparently distinct from transforming growth factor-beta, activin, IL6, epidermal growth factor, atrial natriuretic peptide and gamma-interferon and was heat and acid stable, resistant to collagenase and destroyed by trypsin treatment. We raise the possibility that loss of an inhibitory autocrine loop may contribute to the rapid proliferation of long-term cultured Schwann cells and that an autocrine growth inhibitor may have a role in the cessation of Schwann cell division that precedes differentiation in peripheral nerve development.


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