Inhibition of Melanoma Cell Proliferation by Targeting Wnt/β-catenin Pathway through Sox4 RNA Interference

The effect of siRNA-mediated Sox4 gene silencing on Wnt/β-catenin signaling pathway of human malignant melanoma cell line A375 was investigated.Two types of dsRNA targeting Sox4 were constructed and transfected into A375 cells,and untreated cells and cells transfected with scramble RNA were used as blank control and negative control respectively.The expression levels of mRNA and protein of Sox4,Wnt3a,β-catenin and Wnt/β-catenin signaling target gene Survivin were detected after real-time PCR and Western blot respectively.MTT assay was used to measure cell proliferation after Sox4 knockdown.β-catenin/TCF transcription reporter assay was used for assessing Wnt/β-catenin signaling pathway activity.Our results showed that the two types of Sox4 siRNA were transfected into A375 cells successfully.As compared with untreated cells,Sox4 siRNAs had no significant influence on Wnt3a expression,and Sox4 siRNAs led to the decrease of β-catenin at protein level.Wnt/β-catenin signaling pathway activity was inhibited significantly.As a target of Wnt/β-catenin signaling,Survivin was decreased at both mRNA and protein levels,and cell proliferation was attenuated.Our study suggests that Sox4 may play an important role in Wnt/β-catenin signaling pathway in human malignant melanoma cells by regulating β-catenin protein level,indicating that Sox4 is involved in the progression of malignant melanoma through Wnt/β-catenin signaling pathway.

Aberrant expression and function of TCF4 in the proliferation of hepatocellular carcinoma cell line BEL-7402

Wnt signaling pathway is essential for development and tumorigenesis,however,this signaling pathway in the progress of hepatocellular carcinoma (HCC) remains unclear. In this paper,we studied the function of human T-cell transcription factor-4 (TCF4),a key factor of Wnt signaling pathway,on the proliferation of HCC cell line. We showed that the expression of TCF4 mRNA in HCC cell line BEL-7402 was higher than that in immortalized normal liver cell line L02. Blockage of Wnt pathway by △NTCF4,a dominant negative TCF4,could suppress BEL-7402 cells growth and decrease the expression of cyclin D1 and c-myc,two of target genes of Wnt pathway. On the other hand,stimulating Wnt pathway by introducing a degradation-resistant β-catenin S37A could increase BEL-7402 cells proliferation. But all the treatments had no effect on L02 cells. Our data indicated that TCF4 might be another key factor in Wnt pathway involved in HCC cells proliferation and TCF4 could be an effective therapeutic target for suppressing the growth of hepatocellular cancers.

Zebrafish ELL-associated factors Eaf1/2 modulate erythropoiesis via regulating gata1a expression and WNT signaling to facilitate hypoxia tolerance

EAF1 and EAF2,the eleven-nineteen lysine-rich leukemia(ELL)-associated factors which can assemble to the super elongation complex(AFF1/4,AF9/ENL,ELL,and P-TEFb),are reported to participate in RNA polymeraseⅡto actively regulate a variety of biological processes,including leukemia and embryogenesis,but whether and how EAF1/2 function in hematopoietic system related hypoxia tolerance during embryogenesis remains unclear.Here,we unveiled that deletion of EAF1/2(eaf1^(-/-)and eaf2^(-/-))caused reduction in hypoxia tolerance in zebrafish,leading to reduced erythropoiesis during hematopoietic processes.Meanwhile,eaf1^(-/-)and eaf2^(-/-)mutants showed significant reduc-tion in the expression of key transcriptional regulators scl,lmo2,and gata1a in erythropoiesis at both 24 h post fertilization(hpf)and 72 hpf,with gata1a downregulated while scl and lmo2 upregulated at 14 hpf.Mechanistically,eaf1^(-/-)and eaf2^(-/-)mutants exhibited significant changes in the expression of epigenetic modified histones,with a significant increase in the binding enrichment of modified histone H3K27me3 in gata1a promoter rather than scl and lmo2 promoters.Additionally,eaf1^(-/-)and eaf2^(-/-)mutants exhibited a dynamic expression of canonical WNT/β-catenin signaling during erythropoiesis,with significant reduction in p-β-Catenin level and in the binding enrichment of both scl and lmo2 promoters with the WNT transcriptional factor TCF4 at 24 hpf.These findings demonstrate an important role of Eaf1/2 in erythropoiesis in zebrafish and may have shed some light on regeneration medicine for anemia and related diseases and on molecular basis for fish economic or productive traits,such as growth,disease resistance,hypoxia tolerance,and so on.

Transferrin receptor-targeted immunostimulant for photodynamic immunotherapy against metastatic tumors through β-catenin/CREB interruption

The immunosuppressive phenotype of tumor cells extensively attenuates the immune activation effects of traditional treatments.In this work,a transferrin receptor(TfR)targeted immunostimulant(PTI)is fabricated for photodynamic immunotherapy against metastatic tumors by interrupting β-catenin signal pathway.To synthesize PTI,the photosensitizer conjugated TfR targeting peptide moiety(Palmitic-K(PpIX)-HAIYPRH)is unitized to encapsulate the transcription interrupter of ICG-001.On the one hand,the recognition of PTI and TfR can promote drug delivery into tumor cells to destruct primary tumors through photodynamic therapy and initiate an immunogenic cell death with the release of tumorassociated antigens.On the other hand,PTI will interrupt the binding between b-catenin andcAMP response element-binding protein(CREB),regulating the gene transcription to downregulate programmed death ligand 1(PD-L1)while upregulating CeC motif chemokine ligand 4(CCL4).Furthermore,the elevated CCL4 can recruit the dendritic cells to present tumor-specific antigens and promote T cells activation and infiltration,and the downregulated PD-L1 can avoid the immune evasion of tumor cells and activate systemic anti-tumor immunity to eradicate lung metastasis.This work may inspire the development of antibody antibody-free strategy to activate systemic immune response in consideration of immunosuppressive conditions.