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B cells play a crucial role in the pathogenesis of various diseases, such as autoimmune disorders, cancers, and infections. Unlike regulatory T cells, the anti-inflammatory capabilities of B cells have only recently garnered attention. Cytokines IL-10 and TGF-β are among the key secreted immunosuppressive factors, therefore studying the characteristics of their transcriptional regulation in B cells appears to be a relevant task. This study focuses on characterizing the promoter regions of IL10 and TGFB1 genes in immortalized B cell lines representing different developmental stages – Reh and Raji. To achieve this, we identified potential promoter regions guided by the epigenetic features of functional regulatory regions determined by bioinformatics methods of ChIP-Seq data analysis of chromatin marks in CD19+ lymphocytes. We examined the activity of selected promoters using reporter analysis in B cells. Additionally, we studied the impact of a single nucleotide polymorphism rs1800469 in the TGFB1 promoter, which is associated with the development of colorectal cancer, chronic obstructive pulmonary disease, and the risk of radiation fibrosis. Our results showed increased promoter activity of IL10 and TGFB1 in the Reh pro-B cells compared to the Raji mature B cells upon stimulation. Interestingly, the presence of the minor allele of rs1800469 led to enhanced TGFB1 promoter activity in the Reh cells. Higher activity of IL10 and TGFB1 promoters in acute lymphoblastic leukemia Reh cells may be associated with the increased immunosuppression, which is characteristic of this pathology. It is also possible that activation of pro-B cells Reh induces their differentiation into monocyte-like cells, which can be polarized into alternatively activated (M2) macrophages by autocrine TGF-β and IL-10. M2 macrophages can function as tumor-associated macrophages and contribute to the development of colorectal cancer. Moreover, increased levels of TGF-β in tissues increase the risks of fibrosis and decrease inflammation levels in chronic obstructive pulmonary disease.

The transcription factor STAT3 serves as an immunoregulator by playing a crucial role in cytokine receptor signaling. However, in various cancer cell types, STAT3 is involved in the molecular mechanisms of oncogenesis. Specifically, in glioblastoma, the STAT3 immunoregulator has been linked to resistance to temozolomide, the most commonly used chemical agent for treating this type of cancer. Furthermore, literature suggests that activation of this oncogene in glioblastoma cells can significantly impact the tolerogenic tumor microenvironment, weakening the antitumor immune response and contributing to the aggressive course of the disease. Therefore, suppressing STAT3 may not only affect cell growth and resistance to chemotherapy but also enhance the immune response by improving the tumor microenvironment.The development of sequencing technologies has revealed that most of the transcribed material in the cell is noncoding. Long non-coding RNAs are gaining popularity in the study of oncogenesis due to their functional role in the development of various diseases, including oncology. A subtype of long non-coding RNAs transcribed from enhancer elements, known as enhancer RNAs, has garnered attention due to their high specificity in various cells and tissues. Gene co-expression analysis in glioblastoma tumors showed a correlation between STAT3 expression and the enhancer RNA LINC00910, which is located in the same chromosomal domain as the Stat3 gene. Previous literature has shown that LINC00910 is associated with both colorectal and gastric cancer. Additionally, data from the GeneHancer database suggests that the enhancer RNA LINC00910 may be involved in regulating the STAT3 immunoregulator. RNA interference was used to effectively knockdown the enhancer RNA LINC00910, resulting in an 8- to 10-fold reduction in its expression in glioblastoma cell lines. The reduction of LINC00910 expression did not significantly affect Stat3 gene expression in glioblastoma cell lines DBTRG-05MG and U251. This suggests that the correlation between LINC00910 RNA expression and STAT3 gene expression is not due to LINC00910’s direct involvement in STAT3 gene regulation in these cells. Further studies using the selected interfering RNA will help to clarify the role of the enhancer RNA LINC00910 in other signallingsignaling pathways, as well as its potential relationship with cancer development.