Yin Yang 1 suppresses tumor invasion and metastasis in nasopharyngeal carcinoma by negatively regulating eIF4E transcriptional activity and expression.

Tumor metastasis is a leading cause of death in nasopharyngeal carcinoma (NPC) patients. Previous research has identified that transcription factor Yin Yang 1 (YY1) acts as a tumor suppressor that inhibits cell proliferation and tumor growth in NPC; however, the role and the molecular mechanisms of YY1 in NPC invasion and metastasis remain unclear. In this study, we discovered that YY1 could inhibit the migration and invasion of NPC cells in vitro as well as NPC xenograft tumor metastasis in vivo. Furthermore, we identified eIF4E as a direct downstream target of YY1, and YY1 could negatively regulate the expression of eIF4E at transcriptional level. Moreover, we found that eIF4E promoted the migration and invasion of NPC cells as well as NPC lung metastasis, suggesting its potential as a pro-metastatic mediator in NPC. Importantly, restoring eIF4E expression could partially reverse the inhibitory effects of YY1 on NPC malignancy. In consistent with these findings, the expression of YY1 was downregulated while eIF4E was upregulated in NPC patients with metastasis, and there was a negative correlation between YY1 and eIF4E expression. Collectively, our results indicate that YY1 suppresses the invasion and metastasis of NPC by negatively regulating eIF4E transcription. Therefore, targeting the YY1/eIF4E transcriptional axis could be a potential therapeutic strategy for the treatment of patients with NPC.

YAP1 synergize with YY1 transcriptional co-repress DUSP1 to induce osimertinib resistant by activating the EGFR/MAPK pathway and abrogating autophagy in non-small cell lung cancer.

YAP1 is a well-known core effector of the Hippo pathway in tumors, but its potential role in osimertinib resistance remained unexplored. Our study provides evidence that YAP1 acts as a potent promoter of osimertinib resistance. By inhibiting YAP1 with a novel inhibitor, CA3, and combining it with osimertinib, we observed a significant suppression of cell proliferation and metastasis, induction of apoptosis and autophagy, and a delay in the emergence of osimertinib resistance. Interestingly, CA3 combined with osimertinib executed its anti-metastasis and pro-tumor apoptosis in part through autophagy. Mechanistically, we found that YAP1, in collaboration with YY1, transcriptionally represses DUSP1, leading to the dephosphorylation of the EGFR/MEK/ERK pathway and YAP1 phosphorylation in osimertinib-resistant cells. Our results also validate that CA3, in combination with osimertinib, executes its anti-metastasis and pro-tumor apoptosis partly through autophagy and the YAP1/DUSP1/EGFR/MEK/ERK regulatory feedback loop in osimertinib-resistant cells. Remarkably, our findings illustrate that YAP1 protein is upregulated in patients after osimertinib treatment and osimertinib resistance. Overall, our study confirms that the YAP1 inhibitor CA3 increases DUSP1 with concomitant activation of the EGFR/MAPK pathway and induces autophagy to enhance the efficacy of third-generation EGFR-TKI treatments for NSCLC patients.

Zinc-finger protein YY1 suppresses tumor growth of human nasopharyngeal carcinoma by inactivating c-Myc-mediated microRNA-141 transcription.

Yin Yang 1 (YY1) is a zinc-finger protein that plays critical roles in various biological processes by interacting with DNA and numerous protein partners. YY1 has been reported to play dual biological functions as either an oncogene or tumor suppressor in the development and progression of multiple cancers, but its role in human nasopharyngeal carcinoma (NPC) has not yet been revealed. In this study, we found that YY1 overexpression significantly inhibits cell proliferation and cell-cycle progression from G1 to S and promotes apoptosis in NPC cells. Moreover, we identified YY1 as a component of the c-Myc complex and observed that ectopic expression of YY1 inhibits c-Myc transcriptional activity, as well as the promoter activity and expression of the c-Myc target gene microRNA-141 (miR-141). Furthermore, restoring miR-141 expression could at least partially reverse the inhibitory effect of YY1 on cell proliferation and tumor growth and on the expression of some critical c-Myc targets, such as PTEN/AKT pathway components both in vitro and in vivo We also found that YY1 expression is reduced in NPC tissues, negatively correlates with miR-141 expression and clinical stages in NPC patients, and positively correlates with survival prognosis. Our results reveal a previously unappreciated mechanism in which the YY1/c-Myc/miR-141 axis plays a critical role in NPC progression and may provide some potential and valuable targets for the diagnosis and treatment of NPC.

The eIF4E/eIF4G interaction inhibitor 4EGI-1 augments TRAIL-mediated apoptosis through c-FLIP Down-regulation and DR5 induction independent of inhibition of cap-dependent protein translation.

The small molecule 4EGI-1 was identified as an inhibitor of cap-dependent translation initiation owing to its disruption of the eIF4E/eIF4G association through binding to eIF4E. 4EGI-1 exhibits growth-inhibitory and apoptosis-inducing activity in cancer cells; thus, we were interested in its therapeutic efficacy in human lung cancer cells. 4EGI-1, as a single agent, inhibited the growth and induced apoptosis of human lung cancer cells.When combined with the death ligand tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), enhanced apoptosis-induced activity was observed. As expected, 4EGI-1 inhibited eIF4E/eIF4G interaction and reduced the levels of cyclin D1 and hypoxia-inducing factor-1alpha (HIF-1alpha), both of which are regulated by a cap-dependent translation mechanism. Moreover, 4EGI-1 induced CCAAT/enhancer-binding protein homologous protein-dependent DR5 expression and ubiquitin/proteasome- mediated degradation of cellular FLICE-inhibitory protein (c-FLIP). Small interfering RNA-mediated blockade of DR5 induction or enforced expression of c-FLIP abrogated 4EGI-1's ability to enhance TRAIL-induced apoptosis, indicating that both DR5 induction and c-FLIP down-regulation contribute to enhancement of TRAIL-induced apoptosis by 4EGI-1. However, inhibition of eIF4E/eIF4G interaction by knockdown of eIF4E effectively reduced the levels of cyclin D1 and HIF-1alpha but failed to induce DR5 expression, downregulate c-FLIP levels, or augment TRAIL-induced apoptosis. These results collectively suggest that 4EGI-1 augments TRAIL-induced apoptosis through induction of DR5 and down-regulation of c-FLIP, independent of inhibition of cap-dependent protein translation.

Effect of Yangqixue Qufengshi Recipe on rheumatoid arthritis model mice under different genetic backgrounds.

OBJECTIVE: To study the effect of Yangqixue Qufengshi Recipe (YQXQFS) on rheumatoid arthritis (RA) model mice under different genetic backgrounds. METHODS: Collagen Induced Arthritis (CIA) were established on HLA-DR4 transgenic (TG) mice and non-transgenic (NTG) mice, which partly were raised with YQXQFS, and the onset day of CIA, the level of type II collagen (CII)-reactive antibodies and the pathological scores of CIA were assessed. RESULTS: Under HLA-DR4 TG background (compared with NTG mice), the earlier onset day of CIA (11.22 +/- 3.35 days vs 16.56 +/- 4.75 days, P < 0.05) and higher level of CII-reactive antibodies (0.2274 +/- 0.1390 microg/ml vs 0.1101 +/- 0.0560 microg/ml, P < 0.05) were observed, but the pathological scores of CIA remained unchanged. YQXQFS could not influence the onset day of CIA and the level of CII-reactive antibodies, but had a certain effect on the total pathological scores (6.56 +/- 3.43 scores vs 11.11 +/- 5.64 scores) and bone erosion (0.22 +/- 0.44 scores vs 1.67 +/- 1.50 scores) of CIA on NTG mice (P < 0.05), NTG YQXQFS group compared with NTG experimental group. CONCLUSION: YQXQFS had a certain effect on RA model, but had no significant effect on HLA-DR4 related CIA.