Wilm′s tumor gene1肽疫苗Galinpepimut-S在肿瘤免疫治疗中的应用

目的为Wilm′s tumor gene1(WT1)肽疫苗Galinpepimut-S(GPS)用于肿瘤免疫治疗的后续研究提供参考。方法采用计算机检索中国知网、PubMed等数据库自建库起至2022年12月的肿瘤免疫治疗相关文献,总结GPS在肿瘤免疫治疗中的应用现状。结果GPS能激发自身免疫系统,对WT1抗原产生强烈免疫反应而发挥抗肿瘤作用,在卵巢癌、恶性胸膜间皮瘤、急性髓系白血病、多发性骨髓瘤的治疗中均显示出较好的疗效。结论以GPS为代表的肿瘤疫苗是未来肿瘤治疗的重要方向,需进一步进行临床研究,以获取更多数据。

Interaction of Human Genes WT1 and CML28 in Leukemic Cells

The molecular pathogenesis of leukemia is poorly understood. Earlier studies have shown both Wilms＇ tumor 1 suppressor gene （WT1） and CML28 abnormally expressed in malignant diseases of the hematopoietic system and WT1 played an important role in leukemogenesis. However, the rela- tionship between molecular CML28 and WT1 has not been reported. Here we described the use of small interfering RNA （siRNA） against WT1 and CML28 in leukemic cell line K562 to examine the interac- tion between CML28 and WT1. WT1 and CML28 gene expression in transfected K562 cells was de- tected by using RQ-PCR and Western blotting. K562 cells transfected with WTI-siRNA could greatly decrease both mRNA and protein expression levels of WT1 and CML28. In contrast, CML28-siRNA did not exert effect on WT1. Further, subcellular co-localization assay showed that the two proteins could co-localize in the cytoplasm of K562 cells, but WT1/CML28 complexes were not detected by us- ing immunoprecipitation. It was suggested that there exists the relationship between CML28 and WT1. CML28 may be a downstream target molecule of WT1 and regulated by WT1, which will provide im- portant clues for further study on the role of CML28 and WT1 in leukemic cells.

Wilms’tumor gene(WT1)is strongly expressed in high-risk subsets of pediatric acute lymphoblastic leukemia

Aim:The purpose of the present study was to perform a comprehensive analysis of WT1 gene expression in high-risk pediatric acute lymphoblastic leukemia(ALL).Methods:We performed a meta-analysis of WT1 gene expression for normal hematopoietic cells vs.primary leukemia cells from 801 pediatric ALL samples deposited in the Oncomine database combined with an in-depth gene expression analysis using our in-house database of gene expression profiles of primary leukemia cells from 1416 pediatric ALL cases.We also examined the expression of WT1 in primary leukemic cells from 299 T-lineage ALL patients in the Oncomine database and 189 T-lineage ALL patients in the archived datasets GSE13159,GSE13351,and GSE13159.Results:Our data provide unprecedented evidence that primary leukemia cells from patients with MLL gene rearrangements(MLL-R)express highest levels of WT1 expression within the high-risk subsets of pediatric B-lineage ALL.Notably,MLL-R^(+)patients exhibited>6-fold higher expression levels of the WT1 gene compared to the other B-lineage ALL subtypes combined(P<0.0001).Our findings in 97 MLL-R^(+)infant B-lineage ALL cases uniquely demonstrated that WT1 is expressed at 1.5-4.2-fold higher levels in MLL-R^(+)infant leukemia cells than in normal hematopoietic cells and revealed that WT1 expression level was substantially higher in steroid-resistant infant leukemia cells when compared to non-leukemic healthy bone marrow cells.Furthermore,our study demonstrates for the first time that the WT1-regulated EWSR1,TP53,U2AF2,and WTAP genes(i.e.,WT1 interactome)were differentially upregulated in MLL-R^(+)leukemia cells illustrating that the MLL-regulatory pathway is aberrantly upregulated in MLL-R^(+)pediatric B-lineage ALL.These novel insights provide a compelling rationale for targeting WT1 in second line treatment of MLL-R^(+)pediatric B-lineage ALL,including MLL-R^(+)infant ALL.Furthermore,our study is the first to demonstrate that leukemia cells from 370 Ph-like patients had significantly higher WT1 expression when compared to normal hematopoietic cells.Finally,our findings demonstrate for the first time that chemotherapy-resistant primarily leukemic cells from relapsed B-lineage ALL patients exhibit higher expression levels of WT1 than primary leukemia cells from newly diagnosed B-lineage ALL patients(P=0.001).Conclusion:Our findings indicate that the WT1 gene product may serve as a target for immunotherapy in high risk/poor prognosis subsets of newly diagnosed as well as relapsed pediatric B-lineage ALL.Our findings also significantly expand the current knowledge of WT1 expression in T-lineage ALL and provide new evidence that WT1 gene and its interactome are expressed in T-lineage ALL cells at significantly higher levels than in normal hematopoietic cells.This previously unknown differential expression profile uniquely indicates that the protein product of WT1 would be an attractive molecular target for treatment of T-lineage ALL as well.

Effects of Bufalin on Up-regulating Methylation of Wilm's Tumor 1 Gene in Human Erythroid Leukemic Cells

Objective To explore the effects of bufalin on inhibiting proliferation, up-regulating methylation of Wilm’ tumor 1 gene (WT1) as well as its possible mechanisms in human erythroid leukemic (HEL) cells. Methods The HEL cells were treated with bufalin at various concentrations to observe cellular morphology, proliferation assay and cell cycle. The mRNA and protein expression levels of WT1 were detected by reverse transcription polymerase chain reaction (RT-PCR), Western blot and immunocytochemistry, DNA methylation of WT1 and protein expression levels of DNA methyltransferase 3a (DNMT3a) and DNMT3b were analyzed by methylation-specific PCR, and Western blot respectively. Results The bufalin was effective to inhibit proliferation of HEL cells in a dose-dependent manner, their suppression rates were from 23.4%±2.1% to 87.2%±5.4% with an half maximal inhibit concentration (IC50) of 0.046 μmol/L. Typical apoptosis morphology was observed in bufalin-treated HEL cells. The proliferation index of cell cycle decreased from 76.4%±1.9% to 49.7%±1.3%. The expression levels of WT1 mRNA and its protein reduced gradually with increasing doses of bufalin, meanwhile, the methylation status of WT1 gene changed from unmethylated into partially or totally methylated. While, the expression levels of DNMT3a and DNMT3b protein gradually increased by bufalin treatment in a dose-dependent manner. Conclusions Bufalin can not only significantly inhibit the proliferation of HEL cells and arrest cell cycle at G0/G1 phase, but also induce cellular apoptosis and down-regulate the expression level of WT1. Our results provide the evidence of bufalin for anti-leukemia, its mechanism may involve in increasing WT1 methylation status which is related to the up-regulation of DNMT3a and DNMT3b proteins in erythroid leukemic HEL cells.