RESUMO
BACKGROUND: Impaired miRNAs processing pathway is one interesting scenario for global downregulation of the miRNAome in various types of malignancy. We previously reported that DGCR8 and Dicer genes dysregulated in patients with breast cancer. OBJECTIVE: To evaluate the expression pattern of Drosha in patients with breast cancer. METHODS: We evaluated the mRNA expression level of Drosha in 70 fresh breast carcinomas and adjacent non-neoplastic tissue using quantitative real-time PCR and assessed the possible correlation between its expression and clinicopathological parameters. RESULTS: Our results revealed that mRNA expression level of Drosha was decreased in tumors when compared to adjacent non-neoplastic tissue. However, this difference is not statistically significant (P > 0.05). Downregulation of Drosha is related to older age at diagnosis, higher histological grade, higher tumor size and metastasis. However, there was no significant correlation between Drosha expression level and clinicopathological parameters (P > 0.05). We found that Drosha expression negatively correlated with DGCR8 (P = 0.043), whereas dysregulated expression levels of Drosha and Dicer are positively correlated with to each other (P < 0.0001). CONCLUSION: This study provides evidence that the expression of Drosha is impaired in breast cancer. However, the molecular basis of observed expression pattern have remained inexplicable and should be further investigated.
Assuntos
Neoplasias da Mama/metabolismo , RNA Mensageiro/análise , Ribonuclease III/genética , Adulto , Idoso , Neoplasias da Mama/patologia , Feminino , Humanos , Pessoa de Meia-Idade , Proteínas de Ligação a RNA/genéticaRESUMO
BACKGROUND: The up-regulation of telomerase gene expression occurs in numerous cancers such as breast cancer. A recent study used the PLGA-PEG-helenalin complex, and free helenalin, to inhibit the expression of telomerase in the breast cancer cell line. The purpose of this study was to examine whether nano encapsulating helenalin improves the anti-cancer effect of free helenalin in the T47D breast cancer cell line. METHOD: The breast cancer cell line (T47D) was grown in the RPMI 1640 medium, supplemented with 10% FBS. The helenalin was encapsulated by the double emulsion method. Then, the drug loading was calculated and its morphology identified by SEM. Other properties of this copolymer were characterized by Fourier transform infrared (FTIR) spectroscopy and H nuclear magnetic resonance (H NMR) spectroscopy. The assessment of drug cytotoxicity on the growth of the breast cancer cell line was carried out through MTT assay. After treating the cells with a given amount of drug, RNA was extracted and cDNA was synthesized. In order to assess the amount of telomerase gene expression, real-time PCR was performed. RESULTS: With regard to the amount of the drug loaded, IC50 value was significantly decreased in nanocapsulated (NC) helenalin, in comparison with that of free helenalin. This finding has been proved through the decrease of telomerase gene expression by real-time PCR. CONCLUSION: In this study, we demonstrated that the NC-helenalin complex is more effective than free helenalin in inhibiting the growth of breast cancer cells.
Assuntos
Neoplasias da Mama/patologia , Portadores de Fármacos/química , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Nanocápsulas/química , Sesquiterpenos/química , Sesquiterpenos/farmacologia , Telomerase/genética , Antineoplásicos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Portadores de Fármacos/toxicidade , Humanos , Ácido Láctico/química , Nanocápsulas/toxicidade , Tamanho da Partícula , Polietilenoglicóis/química , Ácido Poliglicólico/química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Reação em Cadeia da Polimerase em Tempo Real , Segurança , Sesquiterpenos de GuaianoRESUMO
BACKGROUND: Nowadays, the encapsulation of cytotoxic chemotherapeutic agents is attracting interest as a method for drug delivery. We hypothesized that the efficiency of helenalin might be maximized by encapsulation in ß-cyclodextrin nanoparticles. Helenalin, with a hydrophobic structure obtained from flowers of Arnica chamissonis and Arnica Montana, has anti-cancer and anti-inflammatory activity but low water solubility and bioavailability. ß-Cyclodextrin (ß-CD) is a cyclic oligosaccharide comprising seven D-glucopyranoside units, linked through 1,4-glycosidic bonds. MATERIALS AND METHODS: To test our hypothesis, we prepared ß-cyclodextrin- helenalin complexes to determine their inhibitory effects on telomerase gene expression by real-time polymerase chain reaction (q-PCR) and cytotoxic effects by colorimetric cell viability (MTT) assay. RESULTS: MTT assay showed that not only ß-cyclodextrin has no cytotoxic effect on its own but also it demonstrated that ß-cyclodextrin- helenalin complexes inhibited the growth of the T47D breast cancer cell line in a time and dose-dependent manner. Our q-PCR results showed that the expression of telomerase gene was effectively reduced as the concentration of ß-cyclodextrin-helenalin complexes increased. CONCLUSIONS: ß-Cyclodextrin-helenalin complexes exerted cytotoxic effects on T47D cells through down-regulation of telomerase expression and by enhancing Helenalin uptake by cells. Therefore, ß-cyclodextrin could be superior carrier for this kind of hydrophobic agent.