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Bernard Desoize

Publications and source records attributed to Bernard Desoize.

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Particular aspects of platinum compounds used at present in cancer treatment.

The history of platinum in cancer treatment began 150 years ago with the first synthesis of cisplatin; but it was not used in the clinic before 30 years ago. Then 3000 derivatives were synthesised and tested, with poor successes: three other derivatives only are available today. Clearly they are not more active, but they are less toxic than cisplatin, although two, carboplatin and nedaplatin, yield a cross-resistance, while one, oxaliplatin, does not. Their mechanisms of action are similar: these four pro-drugs form adducts with DNA, impairing DNA synthesis and repair then. Their pharmacokinetics are complicated since we always measure two overlapping pharmacokinetics: those of the parent compound and of the bound platinum. Cisplatin is now recommended for few cancers, it is replaced by less-toxic carboplatin, and therefore more easily used in combination. Oxaliplatin give interesting results in a number of cancers. The official recommendation in Japan for nedaplatin is head and neck, testicular, lung, oesophageal, ovarian, and cervical cancer.

Animals↗

Gallium in cancer treatment.

Gallium (Ga) is the second metal ion, after platinum, to be used in cancer treatment. Its activities are numerous and various. It modifies three-dimensional structure of DNA and inhibits its synthesis, modulates protein synthesis, inhibits the activity of a number of enzymes, such as ATPases, DNA polymerases, ribonucleotide reductase and tyrosine-specific protein phosphatase. Ga alters plasma membrane permeability and mitochondrial functions. Ga salts are taken up more efficiently and more specifically by tumour cells when orally administered. New compounds have been prepared: Ga maltolate, doxorubicin-Ga-transferrin conjugate and Tris(8-quinolinolato)Ga(III), which show interesting activities. Ga toxicity is well documented in vitro and in vivo in animals. In humans, the oral administration Ga is less toxic, and allows a chronic treatment, allowing an improvement of its bioavailability in tumours, by comparison with the parenteral use. The anticancer activity of Ga salts has been demonstrated but other effects have also been noted such as many bone effects that could be useful in bone metastatic patients. Its has also been shown that a long period of administration could induce tumour fibrosis. Ga is synergistic with other anticancer drugs. Although not as potent as platinum in vitro, the anticancer activity of Ga should not be ignored, but the schedule of administration still needs to be optimised and new compounds are now under clinical investigations.

Animals↗

Metals and metal compounds in carcinogenesis.

Several metals and metal containing compounds are potent mutagens and carcinogens. The most often blamed are chromium, arsenic, nickel, vanadium, iron, copper and manganese. Although each of them has its own mechanism of action, it is believed that most of their mechanisms of action involve reactive oxygen species (ROS). Furthermore, nickel modulates gene expression by induction of DNA methylation and/or suppression of histone acetylation. Arsenic activity on cell metabolism is multiple; it seems that cell transformation is induced by long-term exposure to a low level of arsenic. The paradox of arsenic is that it has also a valuable therapeutic efficacy in cancer treatment. Manganese is known to cause DNA damage, although it does not represent a significant carcinogenic risk. Magnesium deficiency and iron excess are not exactly carcinogenetic, but certain concentrations of these metal ions are needed to prevent cancer.

Carcinogens↗

Metals and metal compounds in cancer treatment.

Metals and metal compounds have been used in medicine for several thousands of years. In this review we summarized the anti-cancer activities of the ten most active metals: arsenic, antimony, bismuth, gold, vanadium, iron, rhodium, titanium, gallium and platinum. The first reviewed metal, arsenic, presents the anomaly of displaying anti-cancer and oncogenic properties simultaneously. Some antimony derivatives, such as Sb2O3, salt (tartrate) and organic compounds, show interesting results. Bismuth directly affects Helicobacter pylori and gastric lymphoma; the effects of bismuth complexes of 6-mercaptopurine are promising. Gold(I) and (III) compounds show anti-tumour activities, although toxicity remains high. Research into the potential use of gold derivatives is still ongoing. Several derivatives of vanadium show anti-proliferative activity, but their toxicity must be overcome. Several pieces of evidence indicate that iron deprivation could be an excellent therapeutic approach; furthermore, it is synergistic with classic anti-cancer drugs. Rhodium belongs to the same group as platinum and it also presents interesting activity, but with the same nephrotoxicity. Several rhodium compounds have entered phase I clinical trials. In contrast to the platinum complexes, titanium derivatives showed no evidence of nephrotoxicity or myelotoxicity; titanocene dichloride is undergoing clinical trial. The anti-proliferative effect of gallium could be related to its competition with the iron atom; in addition a derivative appears to reverse the multidrug resistance. The last metal reviewed, platinum, has given some of the very best anti-cancer drugs. Four derivatives are used today in the clinic; their mechanism of action and of resistance are described.

Animals↗