RESUMO
Pokemon, an important proto-oncoprotein, is a transcriptional repressor that belongs to the POK (POZ and Krüppel) family. Smad4, a key component of TGF-ß pathway, plays an essential role in TGF-ß-induced transcriptional responses. In this study, we show that Pokemon can interact directly with Smad4 both in vitro and in vivo. Overexpression of Pokemon decreases TGF-ß-induced transcriptional activities, whereas knockdown of Pokemon increases these activities. Interestingly, Pokemon does not affect activation of Smad2/3, formation of Smads complex, or DNA binding activity of Smad4. TGF-ß1 treatment increases the interaction between Pokemon and Smad4, and also enhances the recruitment of Pokemon to Smad4-DNA complex. In addition, we also find that Pokemon recruits HDAC1 to Smad4 complex but decreases the interaction between Smad4 and p300/CBP. Taken together, all these data suggest that Pokemon is a new partner of Smad4 and plays a negative role in TGF-ß pathway.
Assuntos
Proteínas de Ligação a DNA/metabolismo , Mapas de Interação de Proteínas/genética , Proteína Smad4/metabolismo , Fatores de Transcrição/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Sítios de Ligação , Proteínas de Ligação a DNA/genética , Células Hep G2 , Humanos , Transdução de Sinais/genética , Proteína Smad2/genética , Proteína Smad2/metabolismo , Proteína Smad3/genética , Proteína Smad3/metabolismo , Proteína Smad4/genética , Fatores de Transcrição/genética , Ativação Transcricional/genética , Fator de Crescimento Transformador beta/farmacologiaRESUMO
Single parent families are at high risk of financial hardship which may impact on psychological wellbeing. This study explored the impact of financial hardship on wellbeing on 15 single parents. Semi-structured interviews were conducted and analysed using constructivist thematic analysis. Participants described food and fuel poverty, and the need to make sacrifices to ensure that children's basic needs were met. In some cases, participants went without food and struggled to pay bills. Isolation, anxiety, depression, paranoia, and suicidal thoughts were described. However, participants reported that psychological services not able to take the needs of single parents in to account. Support for single parents must acknowledge the impact of social circumstances and give more consideration economic drivers of distress.
RESUMO
AIM: To clarify the specific roles and mechanisms of long interspersed nuclear element-1 ORF-1 protein [human long interspersed nuclear element-1 (LINE-1), ORF-1p] in chemotherapeutic drug resistance and cell proliferation regulation in hepatocellular carcinoma (HCC) cells. METHODS: MTT assays were performed to identify the effect of the chemotherapeutic drug toxicity on HepG2 cells. Cell proliferation inhibition and the IC50 were calculated by the Origin 8.0 software. Western blotting assays were performed to investigate whether LINE-1 ORF-1p modulates the expression of some important genes, including p53, p27, p15, Bcl-2, mdr, and p-gp. To corroborate the proliferation and anchor-independent growth results, the HepG2 cells were analyzed by flow cytometry to investigate the effect of LINE-1 ORF-1p on the apoptosis regulation. RESULTS: LINE-1 ORF-1p contributed to the resistance to several chemotherapeutic drugs (cisplatin and epirubicin) in HepG2 cells. The IC50 of the epirubicin and cisplatin increased from 36.04 nmol/L to 59.11 nmol/L or from 37.94 nmol/L to 119.32 nmol/L. Repression of LINE-1 ORF-1p expression by the siRNA could markedly enhance the response of HepG2 cells to the epirubicin and cisplatin. The IC50 correspondingly decreased from 28.06 nmol/L to 3.83 nmol/L or from 32.04 nmol/L to 2.89 nmol/L. Interestingly, down-regulation of LINE-1 ORF-1p level by siRNA could promote the response of HepG2 cells to the paclitaxel. The IC50 decreased from 35.90 nmol/L to 7.36 nmol/L. However, overexpression of LINE-1 ORF-1p did not modulate the paclitaxel toxicity in HepG2 cells. Further Western blotting revealed that LINE-1 ORF-1p enhanced mdr and p-gp gene expression. As a protein arrested in the nucleus, LINE-1 ORF-1p may function through modulating transcriptional activity of some important transcription factors. Indeed, LINE-1 ORF-1p promoted HepG2 cell proliferation, anchor-independent growth and protected the cells against apoptosis through modulating the expression of p15, p21, p53, and Bcl-2 genes. CONCLUSION: LINE-1 ORF-1p promotes HepG2 cell proliferation and plays an important role in the resistance of chemotherapeutic drugs. By establishing novel roles and defining the mechanisms of LINE-1 ORF-1p in HCC chemotherapeutic drug resistance and cell proliferation regulation, this study indicates that LINE-1 ORF-1p is a potential target for overcoming HCC chemotherapeutic resistance.