Dietary polyphenols have been correlated with a reduced risk of developing cancer. Quercetin (a natural polyphenolic compound) induced apoptosis in many human cancer cell lines, including breast cancer MCF-7 cells. However, the involvement of possible signaling pathways and the roles of quercetin in apoptosis are still undefined. The purpose of this study was to investigate the effects of quercetin on the induction of the apoptotic pathway in human breast cancer MCF-7 cells. When MCF-7 cells were treated with quercetin for 24 and 48 h and at various doses (10-175 microM), cell viability decreased significantly in time- and dose-dependent manners. Exposure of MCF-7 cells to 10-175 microM quercetin resulted in an approximate 90.25% decrease in viable cells. To explicate the mechanism underlying the antiproliferative effect of quercetin, cell cycle distribution and apoptosis in MCF-7 cells was investigated after exposure to 150 microM quercetin for 6-48 h. Quercetin caused a remarkable increase in the number of S phase (14.56% to 61.35%) and sub-G1 phase cells (0.1% to 8.32%) in a dose- and time-dependent manner. Quercetin caused S phase arrest by decreasing the protein expression of CDK2, cyclins A and B while increasing the p53 and p57 proteins. Following incubation with quercetin for 48 h, MCF-7 cells showed apoptotic cell death by the decreased levels of Bcl-2 protein and DeltaPsi(m) and increased activations of caspase-6, -8 and -9. Moreover, quercetin increased the AIF protein released from mitochondria to nuclei and the GADD153 protein translocation from endoplasmic reticulum to the nuclei. These data suggested that quercetin may induce apoptosis by direct activation of the caspase cascade through the mitochondrial pathway in MCF-7 cells.
Prostate cancer has its highest incidence and is becoming a major concern. Many studies have shown that traditional Chinese medicine exhibited antitumor responses. Quercetin, a natural polyphenolic compound, has been shown to induce apoptosis in many human cancer cell lines. Although numerous evidences show multiple possible signaling pathways of quercetin in apoptosis, there is no report to address the role of endoplasmic reticulum (ER) stress in quercetin-induced apoptosis in PC-3 cells. The purpose of this study was to investigate the effects of quercetin on the induction of the apoptotic pathway in human prostate cancer PC-3 cells. Cells were treated with quercetin for 24 and 48 h and at various doses (50-200 μM), and cell morphology and viability decreased significantly in dose-dependent manners. Flow cytometric assay indicated that quercetin at 150 μM caused G0/G1 phase arrest (31.4-49.7%) and sub-G1 phase cells (19.77%) for 36 h treatment and this effect is a time-dependent manner. Western blotting analysis indicated that quercetin induces the G0/G1 phase arrest via decreasing the levels of CDK2, cyclins E, and D proteins. Quercetin also stimulated the protein expression of ATF, GRP78, and GADD153 which is a hall marker of ER stress. Furthermore, PC-3 cells after incubation with quercetin for 48 h showed an apoptotic cell death and DNA damage which are confirmed by DAPI and Comet assays, leading to decrease the antiapoptotic Bcl-2 protein and level of ΔΨm , and increase the proapoptotic Bax protein and the activations of caspase-3, -8, and -9. Moreover, quercetin promoted the trafficking of AIF protein released from mitochondria to nuclei. These data suggest that quercetin may induce apoptosis by direct activation of caspase cascade through mitochondrial pathway and ER stress in PC-3 cells.
Melanoma is one of the most common cancers worldwide and its incidence has been increasing over the past few decades. Gallic acid (GA) can inhibit the growth of human cancer cells in vitro and in vivo. However, there is no available information to address the effects of GA on migration and invasion of human skin cancer cells. Matrix metalloproteinases (MMPs), zinc-dependent proteolytic enzymes, play an important role in the invasion, metastasis, and angiogenesis of cancer cells. Therefore, MMPs are one of the targets for agents to suppress and that could inhibit the migration and invasion of cancer cells. GA affected the viable A375.S2 cells by propidium iodide exclusion and flow cytometric analysis. Cell migration and invasion were investigated by Boyden chamber assay and we also determined the levels of protein and mRNA expression cell migration and invasion by gelatin zymography, western blotting, and real-time PCR assays. In this study, we examined the influence of GA on the protein levels and gene expression of MMP-2 and MMP-9 and in-vitro migration and invasiveness of human melanoma cells. GA decreases the MMPs and associated signal pathway protein and MMPs mRNA levels in A375.S2 human melanoma cells. Our findings suggest that GA has antimetastatic potential by decreasing invasiveness of cancer cells. Moreover, this action of GA was involved in the Ras, p-ERK signaling pathways resulting in inhibition of MMP-2 in A375.S2 human melanoma cells. These data, therefore, provide evidence for the role of GA as a potential cancer chemotherapeutic agent, which can markedly inhibit the invasive capacity of melanoma cells.
In this prospective, descriptive study, we used a repeatedmeasures design to explore the 24-hour effects of caregiving and positioning on preterm infants' states and the factors associated with state changes. Thirty preterm infants (gestational age 27.6-36.1 weeks) were observed for 3 days in the neonatal intensive care unit to record six states: quiet sleep (QS), active sleep, transition, active awake, quiet awake, and fussy or crying. The occurrences of QS increased when infants received no caregiving, social interaction, non-nutritive sucking (NNS), and were laterally positioned. However, QS significantly decreased and fussy or crying state increased when infants received routine and intrusive caregiving. These results suggest that caregiving, NNS, and positioning should be appropriately provided to facilitate infants' sleep, and reduce fussiness or crying. ß
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