RESUMO
Radiotherapy is used in breast cancer to destroy tumor cells lingering after surgery. It is accepted that lethal effects of ionizing radiation occur as a result of damage to DNA in irradiated (IR) cells. However, response mechanisms may promote cell survival with efficient DNA repair or genomic alterations. Chromosomal aberrations are frequent in surviving cells and may enhance chromosomal instability (CIN) which is associated with increased risk of recurrence and metastasis. Intercellular communication can affect the response in IR cells and cause damage in non-irradiated (N-IR) cells. We evaluated the effect of the secretome of non-tumorigenic mammary cells (MCF-10A) on proliferation and DNA damage in breast cancer cells (MCF-7 and MDA-MB-231). Results showed that conditioned media from IR and N-IR MCF-10A cells produced cycles of DNA double-strand breaks in N-IR and IR tumor cells leaving them with residual damage. CIN markers (micronuclei, nucleoplasmic bridges, nuclear buds) were also increased in IR and N-IR tumor cells, being the effect of conditioned media from IR MCF-10A greater in many cases. The inhibition of phosphorylation/activation of Src kinase in cancer cells hindered CIN markers' increment. Besides, clonogenic survival of tumor cells was differentially modulated by conditioned media from MCF-10A: decreased in MCF-7 and enhanced in MDA-MB-231 cells. These results signal the relevance of tumor-host interaction in tumor behavior and the response to radiotherapy.
Assuntos
Neoplasias da Mama/genética , Dano ao DNA , Células Epiteliais/efeitos da radiação , Raios gama , Glândulas Mamárias Humanas/citologia , Animais , Apoptose/efeitos da radiação , Linhagem Celular , Proliferação de Células/efeitos da radiação , Células Epiteliais/metabolismo , Feminino , HumanosRESUMO
The aim of this work was to evaluate whether oral administration of Eruca vesicaria, a species of rocket cultivated in Argentina, could modify cyclophosphamide (CP)-induced genotoxicity through modulation of hepatic ABC transporters. Daily oral administration of E. vesicaria fresh leaves juice (1.0, 1.4 and 2.0â¯â¯g/kg) for 14 days did not alter genotoxicity biomarkers -alkaline comet assay and micronucleus test -in neither male nor female mice. Instead, repeated intake of this cruciferous decreased CP-induced DNA damage dose-dependently and it caused hepatic overexpression of P-glycoprotein (P-gp; 1.4 and 2.0â¯â¯g/kg) and multidrug resistance protein 2 (MRP2; 2.0â¯â¯g/kg), but not breast cancer resistance protein (Bcrp). The antigenotoxic effect of E. vesicaria was prevented by 50â¯mg/kg verapamil (P-gp inhibitor) or 10â¯mg/kg indomethacin (MRP2 inhibitor). In turn, CP-induced cytotoxicity (10â¯mM, 24â¯h) on human hepatoma cells (HepG2/C3A) was significantly reduced by preincubation with E. vesicaria (1.4â¯mg/ml; 48â¯h); this effect was absent when CP was coincubated with 35⯵M verapamil, 80⯵M indomethacin or 10⯵M KO-143 (BCRP inhibitor). Altogether, these results allow us to demonstrate that repeated intake of E. vesicaria exhibited antigenotoxicity, at least in part, by induction of hepatic ABC transporters in vivo in mice as well as in vitro in human liver cells. This could account for other diet-drug interactions.
Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Subfamília B de Transportador de Cassetes de Ligação de ATP/metabolismo , Brassica/química , Mutagênese/efeitos dos fármacos , Extratos Vegetais/farmacologia , Substâncias Protetoras/farmacologia , Administração Oral , Animais , Linhagem Celular Tumoral , Ciclofosfamida/farmacologia , Dano ao DNA/efeitos dos fármacos , Feminino , Sucos de Frutas e Vegetais , Humanos , Fígado/metabolismo , Masculino , Camundongos , Mutagênicos/farmacologia , Extratos Vegetais/administração & dosagem , Folhas de Planta/química , Substâncias Protetoras/administração & dosagemRESUMO
Several epidemiological studies have demonstrated that a diet with high contents of cruciferous vegetables (which belong to the Brassicaceae family) may reduce the incidence of cancer and neurodegenerative diseases. However, some authors have postulated that they might bring about toxic effects. Therefore, the aim of this study was to assess the effects of chronic administration of Diplotaxis tenuifolia (wild rocket), a species found in Argentina, concerning its putative genotoxicity or antigenotoxicity against the DNA damage inducer cyclophosphamide, and its ability to modulate the hepatic expression of ABC efflux transporters on mice. The alkaline comet assay and the micronucleus test were used as genotoxicity biomarkers, and the ABC transporter expression was analyzed by Western-blotting. D. tenuifolia juice exhibited no genotoxicity in any of the three tested doses (pâ¯>â¯0.05), showing instead a protective effect against genotoxic damage induced by cyclophosphamide (pâ¯<â¯0.001) in a dose-dependent behavior. Furthermore, hepatic expression of ABCB1 remained unchanged in both sexes at every dose, whereas ABCG2 expression increased in females (pâ¯<â¯0.05) and males (pâ¯<â¯0.01) at the highest dose. Regarding ABCC2, sex-related differences were observed (pâ¯<â¯0.05), its expression decreasing in females (pâ¯<â¯0.05) and increasing in males (pâ¯<â¯0.05). The modulation of these transporters may contribute to the antigenotoxic effects of D. tenuifolia since they act as universal detoxifiers, excreting xenobiotics to the cellular exterior. Phytochemicals present in the juice such as glucosinolates, quercetin and kaempherol may be responsible for these beneficial effects.
Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Brassicaceae/química , Ciclofosfamida/toxicidade , Dano ao DNA , Fígado/efeitos dos fármacos , Mutagênicos/toxicidade , Extratos Vegetais/farmacologia , Animais , Medula Óssea/efeitos dos fármacos , Medula Óssea/metabolismo , Medula Óssea/patologia , Feminino , Fígado/metabolismo , Fígado/patologia , Masculino , CamundongosRESUMO
The present study was carried out to investigate the genotoxicity as well as possible protective activity against damage induced by cyclophosphamide (CP) of the aqueous juice of watercress (Nasturtium officinale, W.T. Aiton) in vivo. Male and female Swiss mice 7-8 weeks old (N = 48) were treated by gavage with 1 g kg(-1) body weight and 0.5 g kg(-1) body weight of watercress juice during 15 consecutive days. Genotoxicity and its possible protective effect were tested by the comet assay in peripheral blood cells and the micronucleus test in bone marrow. In addition, biopsies of the bladder, epididymis and testicles of mice were performed to extend the experimental design. Watercress juice per se did not induce genetic damage according to the comet assay and micronucleus study, exhibiting a protective activity against CP (P < 0.05 and P < 0.001, respectively). The comparative analysis of bladder histological changes obtained in the watercress plus CP group against those treated with CP alone suggests a probable protective effect. Further studies are needed in order to establish the protective role of watercress juice against DNA damage.