Identification of Significant Pathways Induced by PAX5 Haploinsufficiency Based on Protein-Protein Interaction Networks and Cluster Analysis in Raji Cell Line

Correlation of Genetic Variants and the Incidence, Prevalence and Mortality Rates of Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is the most common cancer during childhood, representing about 30–35% of cases. Its etiology is complex and not fully understood. ALL is influenced by genetic variants, and their frequencies (Fq) vary in different ethnic groups, which consequently could influence the epidemiology of this cancer worldwide. The aim of this study was to investigate the correlation between the genetic variants and their impacts on incidence (IC), mortality (MT), and prevalence (PV) rates of ALL in different world populations. Methods: Sixty variants were selected from the literature with Genome Wide Association studies (GWAS). Information regarding allele Fq was selected from the 1000 Genomes platform. Epidemiological data were taken from the Global Burden of disease visualisations (GBD) Compare website. Statistical analyses were calculated in RStudio v.3.5.1 software. Results: Four variants demonstrated significant results in correlations with epidemiological data for ALL. The PAX5 gene variant (rs2297105) had an indirect relationship with PV and IC of ALL, showing that an increased Fq of this variant is related to low rates of both. An increased Fq of rs915172 in EPB4IL2 gene was also correlated with a lower IC of ALL. The rs1048943 of the CYP1A1 gene and the rs3088440 polymorphism of the CDKN2A gene were shown to have a direct proportional relationship with MT rate, showing that an increased Fq of these variants correlates with a worse prognosis worldwide. Conclusion: Our study points out four important variants for understanding the IC, PV, and MT rates for ALL. The ascertainment of these data may help to choose molecular markers to investigate the susceptibility and prognosis of ALL.

PAX5 haploinsufficiency induces low T cell infiltration in the cancer microenvironment via reduced chemokines

AIMS

To investigate the effects of PAXT mutations on tumor immunity.

BACKGROUND

Loss of function of PAX5 plays a key role in PAX5 mutation tumor.

OBJECTIVE

PAX5 haploinsufficiency promoting tumorigenesis is related to immune escape, but there was no report about mechanisms of PAX5 mutation inducing tumor immunological escape.

METHOD

We constructed the PAX5 haplodeletion A20 cell lines using gene-editing technology, built allografted A20 tumor models and evaluated the effect of PAX5 haplodeletion on T cells and chemokines in the tumor microenvironment (TME).

RESULT

Our results from different methods indicated percentages of CD3+ CD4+ T cells and CD3+ CD8+ T cells in TME of PAX5 haplodeletion clones decreased significantly compared with that of PAX5 wild type control. Several chemokines, such as Ccl2, Ccl4, Cxcl9 and Cxcl10, in TME of PAX5.

CONCLUSION

Our study showed that PAX5 haploinsufficiency induced low T cell infiltration in TME using decreased chemokines.

PAX5 haploinsufficiency induced CD8+ T cells dysfunction or exhaustion by high expression of immune inhibitory-related molecules

PURPOSE

PAX5 haploinsufficiency promoting tumorigenesis is related to immune escape. But the mechanisms of PAX5 mutations inducing tumor immune escape have not been clarified. Our aim was to study how PAX5 haploinsufficiency influences effector CD8 + T cells in tumor microenvironment.

METHODS

We estimated the proportions of 22 immune cell types and the expressions of immune inhibitory-related molecules based on gene expression profiles (GEPs) from children's B- acute lymphoblastic leukemia(B-ALL) with PAX5 mutations by CIBERSORT, an established algorithm. We constructed the PAX5 haplodeletion A20 cell lines, built allografted A20 tumor models and evaluated the effect of PAX5 haplodeletion on immune inhibitory-related molecules in the tumor microenvironment (TME).

RESULTS

Our results indicated the percentages of T cells in bone marrow of children's B-ALL with PAX5 mutations were not statistically different from that in bone marrow of B-ALL without PAX5 mutations, except for T follicular helper (Tfh) cells. But a variety of up-regulated immune inhibitory-related molecules in bone marrow of children's B- ALL with PAX5 mutations were identified. By different approaches, we found that several immune inhibitory-related molecules of CD8+ T cells in TME of PAX5 haplodeletion clones such as TIM3, NR4A1 and BATF, were increased significantly compared with that of PAX5 wild type control. The IFN-ɤ of CD8+ T cells in TME of PAX5 haplodeletion tumors was decreased significantly compared with that of PAX5 wild type control.

CONCLUSION

Our study showed that PAX5 haploinsufficiency induced CD8+ T cells dysfunction or exhaustion by high expression of TIM3, NR4A1 and BATF in the CD8+ T cells of TME.

Deletion of MBD2 inhibits proliferation of chronic myeloid leukaemia blast phase cells

Aberrant methylation of tumour suppressor genes is associated with the progression to a blast crisis in chronic myeloid leukaemia (CML). Methyl-CpG-binding domain protein 2 (MBD2) has been studied as a "reader" of DNA methylation in many cancers, but its role in CML is unclear. We constructed cell models of a homozygous deletion mutation of MBD2 using gene-editing technology in K562 cells and BV173 cells. Here, we demonstrated that the deletion of MBD2 inhibited cell proliferation capacity in vitro. MBD2 deletion also significantly inhibited K562 cell proliferation in a xenograft tumour model in vivo. Additionally, the JAK2/STAT3 signalling pathway, which is abnormally active in CML, was inhibited by MBD2 deletion, and MBD2 deletion could up-regulate the expression of SHP1. In conclusion, our findings suggest that MBD2 is a candidate therapeutic strategy for the CML blast phase.

PAX5 haploinsufficiency induce cancer cell dormancy in Raji cells

PAX5 mutations have important role in leukemogenesis and leukemia relapse, cancer cell dormancy participates in cancer relapse, but there was no report about PAX5 mutation inducing cancer cell dormancy. we constructed the PAX5 deletion Raji cell lines using gene editing technology, evaluated dormancy biological characteristics of cell lines. Our results showed PAX5 haploinsufficiency restrained the proliferation of Raji cells, induced G0/G1 arrest of Raji cells, reduced chemotherapy sensitivity. The tumor formation rate reduced in PAX5 mutation Raji cells. Our results showed PAX5 insufficiency induced cancer cell dormancy in Raji cell.