In-vitro Modulation of mTOR-HIF-1α Axis by TLR7/8 Agonist (Resiquimod) in B-Chronic Lymphocytic Leukemia

Targeting toll-like receptors (TLRs), via TLR agonists, has been implicated in the regulation of immunometabolism. B-chronic lymphocytic leukemia (B-CLL) represents a suitable model for B-cell derived malignancies with shifted metabolic adaptations. Several signaling pathways have been found to be critical in metabolic reprogramming of CLL, including mechanistic target of rapamycin- hypoxia inducible factor-1α (mTOR- HIF-1α) pathway, the main metabolic regulator of glycolysis. Here, we investigated the effect of TLR7/8 agonist (Resiquimod) on the expression of mTOR and HIF-1α in patients with CLL. B cells were purified using Rosettesep Human B cell Enrichment Cocktail (Stem cell Technologies, Vancouver, BC, Canada#15,024) from peripheral venous blood of CLL patients (n = 20) and healthy individuals (n = 15). Isolated B cells were then cultured in both presence and absence of Resiquimod. Gene expression of mTOR and HIF-1α were assessed using qRT-PCR. Resiquimod significantly decreased mTOR and HIF-1α gene expression in both CLL (p < 0.001and p < 0.001, respectively) and Normal B cells (p = 0.004 and p = 0.001, respectively). Resiquimod may reprogram immunometabolism of malignant B-CLL cells via down-regulation of key glycolytic metabolic actors, mTOR and HIF-1α genes. Accordingly, Resiquimod may be an adjuvant as a therapeutic tool for CLL, which needs to be studied further.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12288-023-01649-y.

IL-6 Impairs the Activity of Vitamin D3 in the Regulation of Epithelial-Mesenchymal Transition in Triple Negative Breast Cancer

Objective:

The present study aimed to investigate the possible role of IL-6 and 1α,25-dihydroxyvitamin D3 (1,25D) signaling in epithelial-mesenchymal transition (EMT) and stemness in triple-negative breast cancer (TNBC) cell line.

Methods:

TNBC cell line, HCC 1806, was treated with IL-6 and 1,25D for three and six days. Also, the role of vitamin D receptor (VDR) was studied by transfection of TNBC cell line with VDR gene and transfection efficiency was assessed using Human VDR enzyme-linked immunosorbent assay (ELISA). Changes in E-cadherin gene expression were analyzed by quantitative real-time PCR (qRT-PCR). Also, changes in CD44+ cells were analyzed by flow cytometry. Finally, morphological changes were investigated by light microscopy after 6 days.

Results:

Treatment of HCC1806 cells with IL-6 has no significant effect either on E-cadherin gene expression or CD44+ cells, (p > 0.05). However, E-cadherin gene expression was significantly up-regulated after treatment with 1,25D for 6 days, (p < 0.05). Also, CD44+ cells were significantly reduced after treatment with 1,25D either for 3 or 6 days, (p < 0.05). Transfection of TNBC cell line with VDR gene significantly up-regulated VDR protein expression, (p < 0.05). In addition, overexpression of VDR in TNBC cells and treatment with 1,25D significantly up-regulated E-cadherin gene expression, (p < 0.05) and reduced CD44+ cells, (p < 0.05). Moreover, transfection with VDR and treatment with a combination of 1,25D and IL-6 significantly down-regulated E-cadherin gene expression and increased CD44+ cells compared with transfected cells with VDR treated with 1,25D alone, (p < 0.05). No significant morphological changes were observed in treated cells, 6 days post-treatment.

Conclusion:

The presence of IL-6 in the breast tumor microenvironment may impair the activity of vitamin D3 signaling, limiting its anti-tumor effects in TNBC.

Leukocytic-vascular endothelial growth factor and integrin alphavbeta3 in acute myeloid leukemia: relation to clinical outcome

Different signaling routes seem to be simultaneously triggered in leukemia, with distinct and overlapping activities. Different reports emphasize the interaction between vascular endothelial growth factor (VEGF) and integrin alphavbeta3 as a key control system of angiogenesis, oncogenesis and metatasis. The current study was undertaken to investigate leukocytic-VEGF and integrin alphavbeta3 as correlated with clinical outcome in patients with acute myeloid leukemia (AML). The study groups included 10 newly diagnosed AML patients before the start of any chemotherapeutic medication and 10 normal healthy control subjects. The level of VEGF was estimated in culture supernatant of peripheral blood mononuclear cells (PBMN) of both groups using commercially available ELISA kit. The degree of integrin alphavbeta3 expression on PBMN was estimated by indirect immunoflourescence. Obtained results showed that the level of VEGF and degree of expression of integrin alphavbeta3 were significantly higher in AML patients than in normal healthy subjects. However, no significant correlation was observed between the levels of VEGF and the degree of expression of integrin alphavbeta3. When clinical findings were concerned, there was a significant positive correlation between VEGF and the percentage of blasts, both in peripheral blood & bone marrow. On the other hand, such correlations were not observed in case of integrin alphavbeta3. In addition no significant correlation was observed between either VEGF or integrin alphavbeta3 and clinical staging, age, and sex. In conclusion, our results proved the importance of VEGF and integrin alphavbeta3 in the pathogenesis of AML. However, the per se increased production or/and secretion of VEGF and integrin alphavbeta3 by leukemic PBMN cells, respectively can not be used as independent predictor (s) for clinical outcome in AML patients. It is more comprehensive to study changes of intracellular signaling pathways when such critically interacting factors are concerned in the leukemic process.