RESUMEN
BACKGROUND: Psammaplin A (PsA) is a natural product isolated from marine sponges, which has been demonstrated to have anticancer activity against several human cancer cell lines via the induction of cell cycle arrest and apoptosis. New drugs that are less toxic and more effective against multidrug-resistant cancers are urgently needed. METHODS: We tested cell proliferation, cell cycle progression and autophagic cell death pathway in doxorubicin-resistant MCF-7 (MCF-7/adr) human breast cancer cells. The potency of PsA was further determined using an in vivo xenograft model. RESULTS AND CONCLUSION: PsA significantly inhibited MCF-7/adr cells proliferation in a concentration-dependent manner, with accumulation of cells in G2/M phase of the cell cycle. PsA significantly decreased SIRT1 enzyme activity and reduced expression of SIRT1 protein in the cultured cells with greater potency than sirtinol or salermide. Acetylation of p53, a putative target of SIRT1, increased significantly following PsA treatment. In addition, PsA markedly increased the expression levels of autophagy-related proteins. In support of this, it was found that PsA significantly increased the expression of damage-regulated autophagy modulator (DRAM), a p53-induced protein. GENERAL SIGNIFICANCE: The results of this study suggest that PsA is sufficient to overcome multidrug-resistant cancer via SIRT1-mediated autophagy in MCF-7/adr breast cancer cells, indicating that PsA has therapeutic potential for clinical use.
Asunto(s)
Antibióticos Antineoplásicos/farmacología , Autofagia/efectos de los fármacos , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/metabolismo , Disulfuros/farmacología , Doxorrubicina/farmacología , Resistencia a Antineoplásicos/efectos de los fármacos , Sirtuina 1/biosíntesis , Tirosina/análogos & derivados , Acetilación/efectos de los fármacos , Animales , Autofagia/genética , Neoplasias de la Mama/genética , Neoplasias de la Mama/patología , División Celular/efectos de los fármacos , División Celular/genética , Línea Celular Tumoral , Resistencia a Antineoplásicos/genética , Femenino , Fase G2/efectos de los fármacos , Fase G2/genética , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Regulación Neoplásica de la Expresión Génica/genética , Xenoinjertos , Humanos , Proteínas de la Membrana/biosíntesis , Proteínas de la Membrana/genética , Ratones , Ratones Desnudos , Trasplante de Neoplasias , Sirtuina 1/genética , Proteína p53 Supresora de Tumor/genética , Proteína p53 Supresora de Tumor/metabolismo , Tirosina/farmacología , Ensayos Antitumor por Modelo de Xenoinjerto/métodosRESUMEN
Measurable indicators of renal injury are required for the assessment of kidney function after toxicant challenge. In our previous study, pleckstrin homology-like domain, family A, member 3 (Phlda3) was a most greatly up-regulated molecule downstream from p53, culminating with kidney tubular injury. This study investigated the positive feedforward effect of Phlda3 on p53 in an effort to explain the largest increase of Phlda3 in injured tubules and the potential of its urine excretion. qRT-PCR assays confirmed a rapid and substantial increase in Phlda3 messenger RNA (mRNA) in the kidney cortex of mice treated with a single dose of cisplatin. Cisplatin overexpression of Phlda3 was verified by gene set analyses of three different microarray databases. In the immunohistochemistry, Phlda3 staining intensities were augmented in the tubules as kidney injury worsened. Moreover, the urinary content of Phlda3 was increased after cisplatin treatment, as were those of other kidney injury markers (Kim-1 and Timp-1). By contrast, cisplatin failed to increase Phlda3 mRNA in the liver despite hepatocyte necrosis and ensuing increases in serum transaminase activities. In NRK52E tubular cells, siRNA knockdown of Phlda3 enhanced the ability of cisplatin to increase p-Mdm2 presumably via Akt, enforcing the interaction between Mdm2 and p53. Consistently, a deficiency in Phlda3 abrogated p53 increase by cisplatin, indicating that Phlda3 promotes p53 accumulation. Phlda3 overexpression had the opposite effect. In addition, treatment with cyclosporine A or CdCl2, other nephrotoxicants, increased Phlda3 mRNA and protein levels in NRK52E cells, as did cisplatin treatment. Overall, Phlda3 may cause p53 accumulation through a feedforward pathway, facilitating tubular injury and its urine excretion.
Asunto(s)
Lesión Renal Aguda/genética , Cisplatino/toxicidad , Citotoxinas/toxicidad , Túbulos Renales/efectos de los fármacos , Proteínas Nucleares/genética , Proteína p53 Supresora de Tumor/genética , Lesión Renal Aguda/inducido químicamente , Lesión Renal Aguda/patología , Lesión Renal Aguda/orina , Animales , Cloruro de Cadmio/toxicidad , Línea Celular , Ciclosporina/toxicidad , Células Epiteliales/efectos de los fármacos , Células Epiteliales/metabolismo , Células Epiteliales/patología , Regulación de la Expresión Génica , Receptor Celular 1 del Virus de la Hepatitis A , Hepatocitos/efectos de los fármacos , Corteza Renal/efectos de los fármacos , Corteza Renal/metabolismo , Corteza Renal/patología , Túbulos Renales/metabolismo , Túbulos Renales/patología , Hígado/efectos de los fármacos , Masculino , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Ratones , Ratones Endogámicos C57BL , Proteínas Nucleares/antagonistas & inhibidores , Proteínas Nucleares/orina , Proteínas Proto-Oncogénicas c-akt/genética , Proteínas Proto-Oncogénicas c-akt/metabolismo , Proteínas Proto-Oncogénicas c-mdm2/genética , Proteínas Proto-Oncogénicas c-mdm2/metabolismo , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , Transducción de Señal , Inhibidor Tisular de Metaloproteinasa-1/genética , Inhibidor Tisular de Metaloproteinasa-1/metabolismo , Proteína p53 Supresora de Tumor/agonistas , Proteína p53 Supresora de Tumor/orinaRESUMEN
Melamine-induced nephrotoxicity is closely associated with crystal formation in the kidney caused by combined exposure to melamine (Mel) and cyanuric acid (CA). However, there are few dosage-finding studies for toxicological evaluation of chronic co-exposure to Mel and CA. The objective of this study was to investigate the possible mechanism by which a Mel and CA mixture lead to renal toxicity in rats. Mel and CA were co-administered to rats via oral gavage for 50 days. Nephrotoxicity was determined by measuring blood urea nitrogen (BUN) and serum creatinine (sCr) levels. Relative kidney weights were significantly increased in rats after co-exposure to Mel+CA (63/6.3 or 630/6.3 mg/kg) mixtures. BUN and sCr levels were significantly increased after Mel and CA co-exposure. Taken together, significant increase in KIM-1, NGAL, and calbindin levels were observed in the urine of rats exposed to Mel+CA (63/6.3 or 630/6.3 mg/kg) compared with the corresponding control group. Histological analysis revealed epithelial degeneration and necrotic cell death in the proximal tubules of the kidney after co-exposure to Mel+CA (63/6.3 or 630/6.3 mg/kg). Our data suggest that Mel-mediated renal toxicity may be influenced by CA concentrations in Mel-contaminated milk or foods.