RESUMEN
Fresh loquat leaves have been used as folk health herb in Asian countries for long time, although the evidence supporting their functions is still minimal. This study aimed to clarify the chemopreventive effect of loquat tea extract (LTE) by investigating the inhibition on proliferation, and underlying mechanisms in human promyelocytic leukemia cells (HL-60). LTE inhibited proliferation of HL-60 in a dose-dependent manner. Molecular data showed that the isolated fraction of LTE induced apoptosis of HL-60 as characterized by DNA fragmentation; activation of caspase-3, -8, and -9; and inactivation of poly(ADP)ribose polymerase. Moreover, LTE fraction increased the ratio of pro-apoptotic Bcl-2-associated X protein (Bax)/anti-apoptotic myeloid cell leukemia 1 (Mcl-1) that caused mitochondrial membrane potential loss and cytochrome c released to cytosol. Thus, our data indicate that LTE might induce apoptosis in HL-60 cells through a mitochondrial dysfunction pathway. These findings enhance our understanding for chemopreventive function of loquat tea.
Asunto(s)
Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Bebidas/análisis , Eriobotrya/química , Depuradores de Radicales Libres/farmacología , Leucemia/patología , Extractos Vegetales/farmacología , Antineoplásicos/química , Compuestos de Bifenilo/química , Proliferación Celular/efectos de los fármacos , Depuradores de Radicales Libres/química , Células HL-60 , Humanos , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Proteína 1 de la Secuencia de Leucemia de Células Mieloides/metabolismo , Picratos/química , Extractos Vegetales/química , Regulación hacia Arriba/efectos de los fármacos , Proteína X Asociada a bcl-2/metabolismoRESUMEN
The widely conserved SUF system is involved in Fe-S cluster repair and biogenesis. In cyanobacterium Synechocystis sp. PCC 6803, transcription of the sufBCDS operon encoding the Suf complex is negatively regulated by the upstream sufR gene encoded by the complementary strand. In this report, two promoters for the sufBCDS operon (P1 and P2) and another promoter for sufR (PsufR) was identified, and it was shown that P1 was activated by a shift to high light conditions. We also showed that Thermosynechococcus SufR negatively regulated P1 and PsufR but not P2, in a reconstituted in vitro transcription system using His(6)-tagged RNA polymerase.