TCF3 and ID3 Regulate TSPAN32 Expression in Burkitt Lymphoma

Abstract

Burkitt lymphoma (BL) is an aggressive non-Hodgkin B-cell lymphoma characterised by chromosomal translocations involving the MYC gene, leading to its overexpression and driving uncontrolled proliferation. BL is categorised into endemic, sporadic, and immunodeficiency-associated subtypes, each with distinct clinical and epidemiological features. TSPAN32, a member of the tetraspanin family, plays a key role in B cell development and immune regulation. In this study, we investigated the regulation of TSPAN32 expression in BL subtypes. Our results show that TSPAN32 expression is significantly downregulated in endemic, sporadic, and HIV-associated BL. Notably, this downregulation is independent of Epstein-Barr virus (EBV) infection, as no significant differences in TSPAN32 expression were observed between EBV-positive and EBV-negative BL clones. Functional studies revealed that overexpression of a wild-type ID3 gene, a known repressor of TCF3, and knockdown of TCF3, both led to a significant upregulation of TSPAN32, particularly in BL41 and Daudi cells, which harbour ID3 mutations. Supporting this, ChIP-seq analysis identified TCF3 binding peaks on the TSPAN32 gene, providing mechanistic evidence of its regulation by TCF3. These findings shed light on the complex transcriptional network regulating TSPAN32 and its dysregulation in BL. Overall, our study suggests that TSPAN32 may serve as both a biomarker and a potential therapeutic target for this disease.

Keywords: Burkitt lymphoma; TSPAN32; tetraspanins.

FIGURE 1

TSPAN32 expression during the maturation of murine B cells. Gene expression analysis of TSPAN32 was performed by interrogating the GSE15907 microarray dataset (A). Expression levels of TSPAN32 in BL cell lines, as compared to normal Germinal Center B cells, as determined by interrogating the GSE43677 dataset (B).

FIGURE 2

Heatmap of the genes positively and negatively correlating with TSPAN32 transcriptional levels, as determined by interrogating the GSE43677 dataset (A). Heatmap of the most significant biological processes enriched by the genes positively and negatively correlating with TSPAN32, as determined using the Metascape software (B). Heatmap of the Transcription Factors putatively involved in the regulation of the genes positively and negatively correlating with TSPAN32, as determined using the Metascape software (C).

FIGURE 3

Effect of MYC modulation on TSPAN32 transcriptional levels. Effect of two different shMYC constructs on TSPAN32 mRNA levels, as determined in the GSE119925 dataset (A). Effect of MYC silencing (MYC‐off) and of a MYC inhibitor (MYCi975) on TSPAN32 mRNA levels, as determined using the GSE135800 dataset (B).

FIGURE 4

Effects of TCF3 and ID3 in Burkitt cell lines. Genomic characteristics of the BL cell lines BL‐41, Daudi and Namalwa (A). Proliferation of BL‐41, Daudi and Namalwa cells upon TCF3 and ID3 modulation (B). Expression levels of TSPAN32 mRNA levels in BL‐41, Daudi and Namalwa upon shTCF3 treatment (C). Expression levels of TSPAN32 mRNA levels in BL‐41, Daudi and Namalwa upon ID3 overexpression (D).