Somatic mutations at the T-cell antigen receptor in antineoplastic drug-exposed populations: comparison with sister chromatid exchange frequency

OBJECTIVE: The objective of this study was to assess the genetic effect of occupational exposure to antineoplastic agents. METHOD: The influence of occupational handling of cytotoxic drugs was investigated by monitoring the frequency of sister chromatid exchanges (SCE), the percentage of cells with high frequencies of SCE (high-frequency cells, HFC), and the frequency of somatic mutation at the T-cell receptor (TCR) locus in mononuclear cells of exposed hospital nurses. These parameters were also measured in healthy donors and in cancer patients at the time of the diagnosis and following the administration of high doses of cytotoxic drugs requiring stem cell support. RESULTS: Our results show that (a) SCE and HFC values in occupationally exposed nurses do not differ from controls, (b) patients with newly diagnosed cancer or following chemotherapy show a number of SCE comparable to those of healthy donors, but a significantly different percentage of HFC, (c) cigarette smokers of all categories studied show higher frequencies of SCE and HFC as compared to nonsmokers, but the differences are not statistically significant, (d) the mutation frequency at the TCR locus in oncology nurses is higher, but not significantly different from the frequency in the control group, and (e) the increase of mutation frequency is statistically significant and seems to be dose dependent in patients treated with high-dose chemotherapy. CONCLUSIONS: Our data suggest that SCE frequency and HFC percentage are not reliable indicators of exposure to possible mutagenic/carcinogenic effects of antineoplastic drugs; on the contrary, our observations indicate that anticancer therapy induces somatic mutations at the TCR locus and suggest an association between exposure to cytotoxic agents and the increase in somatic mutations

Toxicity and clinical tolerance of lonidamine

The new anticancer agent lonidamine has been recently revisited for the treatment of various solid tumors, due to its peculiar and unusual mechanism of action (ie, interference with energy metabolism of tumor cells, morphologically displayed by the appearance of "condensed mitochondria"). First generation trials have in fact demonstrated therapeutic activity and an unusual toxicity profile. Lonidamine is devoid of conventional side effects induced by antiproliferative agents (ie, myelosuppression, stomatitis, cystitis, alopecia, renal, hepatic, and cardiac toxicity). No serious or life-threatening adverse reactions have been recorded even over long term treatment periods. Given as a single agent (in daily doses ranging between 300 and 900 mg) lonidamine induces the following side effects: myalgia, testicular pain, asthenia, ototoxicity, nausea and vomiting, gastric pain, and drowsiness. Hyperesthesia and photophobia have also been reported. In combination with radiotherapy (in oral daily doses ranging between 300 and 450 mg) lonidamine was well tolerated, without any reported evidence of additional toxicity. When associated with cytotoxic agents no enhanced toxicity was observed. In particular, myelosuppression and other conventional nonhematological adverse reactions were never greater than would be expected with chemotherapy alone. The same applies to toxicity and tolerance of lonidamine when used concurrently with hypertermia. The data collected from large series of cancer patients treated with this new agent show that lonidamine is a safe drug whether used alone or in combination with other effective anticancer treatments. The reported therapeutic efficacy and the peculiar toxic profile make lonidamine an interesting new drug for future clinical trials

Morphological and biochemical features of a medroxyprogesterone acetate (MPA)-resistant MCF-7 breast cancer cell line

An MCF-7 human breast cancer line variant (MCF-7/MPA), resistant to medroxyprogesterone-acetate (MPA), was obtained by continuous exposure in vitro to the drug. MCF-7/MPA cells were grown in the presence of 12.5 x 10(-6) M MPA and were selected by increasing the concentration of the drug in the growth medium in a stepwise manner from 0.025 x 10(-6) M up to 12.5 x 10(-6) M. Comparative studies of cellular morphology, cytosolic steroid receptor content and P-Glycoprotein expression were performed on both MCF-7 parental line and MCF-7/MPA variant. MCF-7/MPA cells, when compared to the parental line, exhibit a different morphology in terms of membrane alterations, reduced content of cytosolic progesterone receptor, increased expression of P-glycoprotein along with reduction of Doxorubicin (Dx) activity on the growth of MCF-7/MPA resistant cells