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Rotenone, a potent inhibitor of mitochondrial respiration is also an effective antimitotic agent. The addition of either rotenone or Colcemid to exponentially growing Chinese hamster ovary cells resulted in a dramatic increase in mitotic index after 90 min. When the cultures were washed free of the drugs, mitosis was completed and the cells progressed into G 1 at approximately the same rate. Further similarity of rotenone-arrested cells to Colcemid-induced mitotic inhibition was apparent at the ultrastructural level. Mitotic cells treated by either drug contained monopolar spindles with chromosomes grouped around centriole pairs near the cell center. Occasional microtubules were seen near the kinetochore and centrioles. These observations, along with the fact that rotenone inhibited the binding of 3H-colchicine to isolated bovine brain tubulin, suggested that rotenone inhibited mitosis by binding directly to tubulin to prevent microtubule assembly.

The aggregation of rabbit peritoneal exudate polymorphonuclear leucocytes (PMNs) was investigated by following total particle number with time, in a shaken suspension. Aggregation was rapid and essentially complete by 30 min, but could be inhibited by microtubule-blocking agents, adenosine and methyl xanthines. The addition of cyclic adenosine 3':5'-monophosphate (cAMP), or its dibutyryl derivative, also inhibited aggregation slightly, but guanosine nucleotides had no significant effect. By consideration of the maximum inhibition brought about by colchicine or theophylline alone, or the two in combination, it appears that they act at different sites to inhibit aggregation, though the effects of either were partially reversed by the addition of adenine. Adenine, lumicolchicine and high concentrations of vinblastine sulphate (10-4 M), enhanced aggregation.

A strain-specific antimitotic substance is present in large mononucleate amoebae. It inhibits mitosis when injected into amoebae of heterologous strains. The antimitotic substance has been isolated from homogenized cells, and some of its properties have been studied. The results obtained show that the active factor is a protein(s) of molecular weight between 200,000 and one million. The activity of this substance differs from other known antimitotic agents in that its action is strain-specific.

When sea urchin gastrulae are treated with colchicine or hydrostatic pressure the cytoplasmic microtubules disappear, but the ciliary microtubules which make up the ciliary axoneme (9+2) remain. With calcium-free sea water the cytoplasmic microtubules are reduced in number yet the 9+2 complex in the cilia is unaffected. Furthermore during the administration of any of these agents the cilia continue to beat so that functionally as well as morphologically the ciliary microtubules are normal even though the cytoplasmic microtubules are broken down and their presumed function in development is interrupted.

1. 1. When added to tissue cultures of chick fibroblasts, the compounds resulting from the addition of thiolacetic acid to 1:4-quinones give different results according to the number of thiolacetic residues incorporated in the quinone. 1.1. (a) Addition of 1 mol. thiolacetic acid to 1:4-naphthoquinone produces a weak mitotic inhibitor. 1.2. (b) Addition of 2 mol. thiolacetic acid to 1:4-naphthoquinone results in a compound with strong antimitotic properties. 1.3. (c) Addition of 4 mol. thiolacetic acid to 1:4-benzoquinone gives a substance which shows no mitotic inhibition but increases considerably the mitotic count. 2. 2. After addition of mercapto- dl -lactic acid and of β-mercaptopropionic acid to 1:4-naphthoquinone no mitotic inhibition has been observed. 3. 3. The addition of thiolacetic acid to 1:4-naphthoquinone-2:3-epoxide has produced the strongest hydroxylated antimitotic agent so far obtained.

Three Chlamydomonas species with division cycles characterized by the occurrence of 2 to 4 mitoses per cycle, were subjected to chemical or physical antimitotic agents incorporated into or applied to agar on which predominantly single cells were spread. In several cases, the sensitive stages in the cell cycle were determined from the distributions of microcolony sizes at the cessation of cell division. Two species showed a highly specific response to chloramphenicol similar to the response to lethal X-ray doses. The first mitosis of a cycle was sensitive to chloramphenicol, while the second mitosis was resistant. This is inferred from the observation that nearly all colonies were arrested in the 1-, 4-, or 8-cell stage. Most cells went through one complete cycle after plating on chloramphenicol or after irradiation; one-half of the cells did so after a combined treatment. Assays of macromolecular components of chloramphenicol-inhibited cells were consistent with the hypothesis that chloramphenicol acts as an inhibitor of protein synthesis. It has been suggested that X-ray inactivation involves the failure of some process which triggers the first mitosis of the cell cycle, but which is not required for the subsequent mitoses. This process, or some other process occurring at approximately the same stage, is inhibited likewise by chloramphenicol, as is overall protein synthesis. Possibly, some particular protein or ribosomal component, essential at the critical stage, is involved. The pattern of 1-, 4-, and 8-celled colonies formed in the presence of chloramphenicol or after x-irradiation could not be duplicated by the response to ultraviolet irradiation, β-mercaptoethanol, 5-fluorouracil or darkness.

The interaction of seventeen colchicine analogs, vinblastine and podophyllotoxin with rat brain microtubule protein has been sudied by measuring their ability to displace 3H-colchicine. The following analogs competitively displaced 3H-colchicine from rat brain microtubule protein: cholchiceinamide, N-desacetylthiocolchicine, demecolcine, N-acetyliodocolchinol, trimethylcolchicinie acid (TMCA) methyl ether, N-acetylcolchinol, and TMCA ethyl ether. Isocolchicine, isocolchiceinamide, iso-TMCA methyl ether, colchiceine, TMCA, N-benzoyl TMCA, colchicosamide, colchicoside, colchinol and colchinoic acid did not inhibit the binding of 3H-colchicine to rat brain microtubule protein. A good correlation was found between the ability of a given analog to displace 3H-colchicine from rat brain microtubule protein and its antimitotic or antigout properties. Podophyllotoxin and vinblastine, both potent antimitotic agents, inhibited 3H-colchicine binding competitively and non-competitively respectively.

The mechanisms of the biochemical interference of the different antimetabolites, of nitrogen mustards, of colchicin substances and of other anticancerous substances are illustrated, with respect to the processes of cell multiplication.

The development of acquired cell-mediated immunity to infection with Listeria monocytogenes can be blocked by a 15 hr pulse of the antimitotic drug, vinblastine (Vb). The drug has no effect on the host-parasite relationship after 72 hr of infection when a high level of immunity is being expressed, i.e., when infective foci are populated by activated macrophages. Infective foci in mice treated early during infection with Vb do not acquire migrant macrophages, but they become acellular after 48 hr of infection. The results indicate that Vb destroys the dividing precursors of migrant macrophages. The possibility that Vb prevents the activation of these cells by destroying dividing lymphoid cells engaged in the specific immunological phase of the host response is also considered.

In previous studies (1, 2, 3, 4, 5, 6, 7) local administration of 5-Fluorouracil1 (5-FU) was found to have a marked effect upon the natural course of single and multiple basal cell epitheliomas and solar keratoses as well as secondary tumors in the skin. The variables that appeared to influence the effects of 5FU and other topically administered antimitotic agents upon the tumors included: concentration of the agent; use of occlusive dressings; duration of application and nature of the vehicle containing the agent. Comparisons of the effects of preparations containing various concentrations of 5-FU upon large confluent areas of superficial basal cell epitheliomatosis have been reported (3). This report presents a more systematic study to compare the effects of different concentrations of 5-FU concurrently administered by inunction to multiple, superficial, basal cell carcinomas in the same patient.

The syntheses of a variety of 3,4-disubstituted pyrroles including the antimitotic agent Verrucarin E are described. 3,4-Pyrroledicarboxylic esters were prepared through a Diels–Alder reaction. Partial hydrolysis of the diesters gave the 4-ester-3-acids which were modified to achieve the synthesis of a variety of unsymmetrically 3,4-disubstituted pyrroles. Raney nickel reduction of a thiolester gave hydroxymethyl under conditions which left acyl or carbalkoxy substituents unaffected. Pyrrole reactions involving carbanionic reagents are complicated by 1-proton abstraction. Therefore, when necessary, the nitrogen was protected by an N-benzyloxymethyl substituent which can be cleaved to the N-hydroxymethyl derivative by aluminum chloride or by hydrogenolysis. Subsequent treatment with benzyltrimethylammonium hydroxide gave back the pyrrole.

Images Figs. 1-20

SummarySeveral compounds representing various structural modifications of the colchicine molecule were examined for their anti-inflammatory activity in an experimental model of inflammation to determine which parts of the colchicine molecule are necessary for its anti-inflammatory activity. The experimental model of inflammation consisted of mouse paw swelling induced by a subplantar injection of a suspension of microcrystal-line sodium urate. Paw swelling was then measured by the paw immersion technique. The results indicate that the methoxytropone moiety and the nitrogen function of colchicine are essential for anti-inflammatory activity. Complete removal of the nitrogen function of colchicine resulted in a compound with only one-fiftieth the activity of colchicine. Since this substance is known to be a more potent antimitotic agent than colchicine, these results suggest that the anti-inflammatory and antimitotic activities of these compounds are distinct at least in our test system.

SummaryThe drug of choice to be used in the treatment of chronic myeloid leukaemia is Myleran. Total clinical and haematologic remissions are generally, obtained.Other antimitotic agents are efficient, especially in Myleran resistant cases. Radioactive isotopes, such as P32 and A1*" can also be used.Due to more protean aspect of the disease, the treatment of lymphoid leukemia is more difficult. The best drug in such a case is chlorambucil, which can be associated with Rontgen therapy in cases with large lymphadenopathies, or with corticoid hormones in cases with anaemia.Other chemotherapeutic agents have been tested, such as Fe3', Dopan, Sarcolysine, Degranol and Endoxan, but none of them seem better than Myleran and Leukeran.

Mittels tritiummarkiertem SP-I 77 wurde die Verteilung dieses Podophyllumderivates im Organismus des Hundes untersucht. Es zeigte sich, das die geringste SP-I-Menge im Knochenmark auftritt. Nur unbedeutend starker wird SP-I 77 in den innersekretorischen Drusen gespeichert. Hohe SP-I-Werte zeigen hingegen die Hauptstoffwechselorgane Leber und Nieren. In den Hohlorganen Gallenblase und Harnblase treten mit Gallenflussigkeit und Urin sehr hohe SP-I-Werte auf. Die Ausscheidungsgeschwindigkeit des SP-I 77 steigt mit der Therapiedauer.

Cell division of the fission yeast, Schizosaccharomyces pombe, is reversibly inhibited by the antimitotic agent Colcemid (N-deacetyl-N-methylcolchicine) in nutrient medium. Cell growth continiues until all cells become nonseparating cell doublets in a V configuration. Mutants have been isolated capable of uninhibited growth in the presence of concentrations of Colcemid mycostatic for the parent strain.

The selective action of nonantigenic tissue extracts on malignant cells was demonstrated using tissue culture techniques. The mitotic index of three strains of neoplastic cells was significantly reduced by the use of extracts which previously had proven effective in adversely affecting the development of spontaneous neoplasms. Under the same conditions the division rate of normal cells in tissue culture was not affected by the extracts. The malignant cells used were the Krebs 2, Sarcoma 180 and the L1210 leukemia. The normal cells were the L929 fibroblasts and epithelial-like cells from bone marrow and corneal tissue.

Contraction in Spirostomum is apparently directed by 2 antagonistic systems which respond to changes in free calcium concentration. The system responsible for imparting contractile tension consists of bundles of 4-5 nm microfilaments which can be calcium-activated. The second system consists of pellicular microtubules which may have the capacity to impart tensile force and react with each other through cross-bridging. Cells subjected to electrical stimulation to induce contraction in the presence of 0.1 mM 2,4-dinitrophenol and KCN failed to recover their original resting lengths. Similar treatment with colchicine produced the same effect, implying an interruption in the activity or structural integrity of the microtubular system. Treatment with 0.5 µg/ml cytochalasin B inhibited all contractile responses, presumably by blocking the activity of microfilaments.

Griseofulvin has been shown to block mitosis in the fungusBasidiobolus ranarum. A wide range of metabolic inhibitors were used to investigate the relationship between growth rate and mitotic index. On the basis of such experiments inhibitors could be divided into two groups; the first affect the cell during the interphase period, the second affect the cell during mitosis.

A ciliate protozoan (Tetrahymena pyriformis, amicronucleate strain GL), exposed to 5 mg/ml colchicine to prevent cell division, is able to overcome the initial inhibitory effect of the drug both in exponentially growing and in heat-shock synchronized cultures.

The response of sodium urate-induced paw welling in mice to various antimitotic and anti-inflammatory agents was studied. Antimitotics colchicine, vinblastine, vincristine and podophyllotoxin produced a significant suppression of paw swelling at similar dose levels. Desacetamidocolchicine, a more potent antimitotic agent than colchicine, was less active against paw swelling even when given in a 58-fold greater dose than colchicine. Anti-inflammatory agents prednisone and indomethacin inhibited paw swelling but phenylbutazone, even at lethal doses, was inactive in this respect.

The present experiments show that antimitotic agents commonly used in the treatment of neoplastic disorders do not behave uniformly with respect to the action on the blastic transformation of lymphocytes. Furthermore, their action differs according to the experimental procedure, namely whether they are administeredin vivo or added directly to the biological systemin vitro. It can be observed however, that a close relationship exists in thein vitro experiment between the inhibition of the blastic transformation and the antiproliferative effect, as measured by the inhibition of the uptake of tritiated thymidine. It is legitimate to believe that such agents are endowed with different degrees of immunological activity, which may be restrained or elicited according to the circumstances. Such effect should therefore be kept in mind, whenever these agents are given for a clinical treatment.

1. 1. The antimitotic effects produced in tissue cultures of chick fibroblasts by certain mercaptoacetic derivatives of 1:4-naphthoquinone (S-(2-hydroxy-1:4-naphthoquinolyl-3) mercaptoacetic acid, called hydroxy-quo- mo , and S:S(1:4-naphthoquinolyl-2:3)- bis -mercaptoacetic acid, called quo- bis ) and by d -, l - and dl -methionine, is alleviated by applying a mixture of the mercaptoacetic adducts and the methionines to the growing cells. 2. 2. Total alleviation is obtained in the system d -methionine / quo- bis at a ratio d -methionine / quo- bis greater than 10:1. The system d -methionine / hydroxy-quo- mo gives complete alleviation at the ratio d -methionine / hydroxy-quo- mo 100:1. 3. 3. With l -methionine / quo- bis , only partial alleviation is achieved even at a ratio l -methionine / quo- bis 100:1. The mitotic inhibition is completely cancelled, but arrest in metaphase is only partially decreased and there is no inhibition of the chromosomal abnormalities. 4. 4. In the system d -methionine / quo- mo no alleviation has been found. 5. 5. d -Ethionine and d -leucine fail to antagonise the antimitotic effect of quo- bis . 6. 6. The increase of the mitotic count observed after application of the tetramercaptoacetic derivative of 1:4-benzoquinone remains unimpaired by d -methionine. 7. 7. It has been pointed out that the alleviation of the antimitotic action of certain sulphydryl adducts of 1:4-naphthoquinone by means of l -methionine, establishes a connection between the antimitotic effects of these compounds and “active methionine” (adenosine-methionine) and thus with the methyl donating properties of l -methionine.

DESACETYLMETHYLCOLCHICINE (Colcemide) is a natural alkaloid which differs from colchicine in that a methyl group replaces an acetyl group at the N position.1 It is a potent antimitotic agent, and over 30 papers have appeared in the foreign literature between 1953 and 1956 reporting its use in the treatment of chronic myelogenous leukemia.2 3 4 5 6 Recent reports have indicated that because of the rarity of gastrointestinal toxicity, it might be a more useful agent than colchicine and indeed might even replace it in the management of acute gouty arthritis.7 8 9 The case reported below illustrates an unusual and profound toxicity to the hematopoietic . . .

SUMMARYAntimitotic agents induce pathological alterations by suspension of the normal cellular renewal: it results the picture of the so called « aregenerative pathology ». Moreover, they induce cytological abnormalities, like cellular vacuolization, alterations of the enzymatic cellular pattern, cellular giantism, etc. These alterations constitute the « cytological dysplasia by antimitotic drugs ». They are easily recognizable in many organs, i.e. in the haemopoietic system, lungs and pancreas. Particularly evident is the cellular giantism in the labial epithelia: in some of these cells of gynecologically normal women two Barr bodies are observed.

The toxicity of 5-aziridino-2,4-dinitrobenzamide (CB 1954) in the rat at the LD50 dose level resembled the majority of antimitotic agents in causing enteritis, but there was less bone marrow depression than usual. At the minimum toxic dose both of these effects were absent, and the tissues affected were the urinary tract and the liver. In the urinary tract areas of transitional epithelium were replaced by a single layer of macronuclear cells. The main pathologic change in the liver was centrilobular venous thrombosis. With chronic dosage the most serious toxic effect was cataract formation which was associated with, but not necessarily the result of, destruction of lens epithelium.

SYNOPSIS To elucidate further the molecular events required for cytodifferentiation in Stentor coeruleus, the effects of several chemical metabolic inhibitors were tested on the outgrowth in situ of the membranellar cilia of the oral feeding organelle. The chemicals used included several inhibitors of cytoplasmic and mitochondrial protein synthesis (cycloheximide, emetine, and chloramphenicol), and an antimitotic agent (colchicine). Ciliary growth was affected only by colchicine, suggesting that a pool of “ciliary proteins” exists in interphase Stentor of sufficient size to permit complete reformation of the membranellar cilia. The implication of these observations to an understanding of the more complicated process of oral regeneration is discussed.

A method of treating psoriasis without the use of corticosteroids or antimitotic agents is described. A special technique incorporating the use of anthralin is employed with results which are better than any so far published. As well as being effective and inexpensive, the technique is safe, with no systemic side effects. It has been adopted as the standard therapeutic procedure in a number of centers in England and Europe.

Tracer experiments prove that the antimitotic agent narciclasine (6) is biosynthesised from O-methyl-norbelladine (1) by para–para coupling followed by late elimination of two carbon atoms.

A new hydroquinone compound, the internal salt of 2,5-bis-ethylenimino-hydroquinone, has a multiform antimitotic effect and a potent tumor-inhibiting action on a wide spectrum of inoculated tumors of mice and rats. On the other hand, normal tissues undergoing intensive cell division do not appear to be affected adversely from the histological standpoint.

In previous studies (1, 2, 3, 4, 5, 6, 7) local administration of 5-Fluorouracil' (5-FL) was found to have a marked effect upon the natural course of single and multiple basal cell cpitheliomas and solar keratoses as well as secondary tumors in the skin. The variables that appeared to influence the effects of 5FU and other topically administered antimitotic agents upon the tumors included: concentration of the agent; use of occlusive dressings; duration of application and nature of the vehicle containing the agent. Comparisons of the effects of preparations containing various concentrations of 5-FL upon large confluent areas of superficial basal cell epitheliomatosis have been reported (3). This report presents a more systematic study to compare the effects of different concentrations of 5-FU concurrently administered by inunction to multiple, superficial, basal cell carcinomas in the same patient.