Agnieszka Chrobak

Opposite regulation of vitamin D receptor by ATRA in AML cells susceptible and resistant to vitamin D-induced differentiation

Some leukemic cell lines can be driven to differentiate to monocyte-like cells by 1,25-dihydroxyvitamin D(3) (1,25D) and to granulocyte-like cells by all-trans retinoic acid (ATRA). Acute myloid leukemias (AMLs) are heterogeneous blood malignancies characterized by a block at various stages of hematopoietic differentiation and there are more than 200 known chromosome translocations and mutations in leukemic cells of patients diagnosed with AML. Because of the multiplicity in the genetic lesions causing the disease, AMLs are particularly difficult to treat successfully. In particular, various AML cells to a variable degree respond to 1,25D-based differentiation and only one type of AML undergoes successfully ATRA-based differentiation therapy. In this paper we describe that AML cell line KG-1 is resistant to 1,25D-induced monocytic differentiation, while sensitive to ATRA-induced granulocytic differentiation. We show that KG-1 cells have very low level of VDR protein and that expression of VDR mRNA is upregulated by ATRA. We show for the first time that this regulation is cell context-specific, because in another AML cell line, HL60, VDR mRNA is downregulated by ATRA. ATRA-induced VDR protein in cytosol of KG-1 cells can be further activated by 1,25D to induce monocytic differentiation of these cells.

Structure–function analysis of vitamin D2 analogs as potential inducers of leukemia differentiation and inhibitors of prostate cancer proliferation

We characterized a structure-function relationships of four analogs of vitamin D(2) with extended and branched side-chains. We tested their ability to induce differentiation of human acute myeloid leukemia (AML) cells both in vitro and ex vivo. Our experiments on five human cell lines revealed substantial differences among tested analogs. Analogs with side-chains extended by one (PRI-1906) or two carbon units (PRI-1907) displayed similar or elevated cell-differentiating activity in comparison to 1,25-dihydroxyvitamin D(3) (1,25D), whereas further extending side-chain resulted in substantially lower biological activity (PRI-1908 and PRI-1909). Similar pattern of cell-differentiating activities to that observed in human cell lines has also been shown in blast cells isolated from patients diagnosed with AML. The ability of the analogs to activate expression of CYP24A1 gene has been studied in HL60 cell line. The analog PRI-1906 activated expression of CYP24A1 similarly to 1,25D, while PRI-1907 weaker than 1,25D. In addition, the analogs PRI-1906 and PRI-1907 were able to moderately inhibit proliferation and significantly activate expression of CYP24A1 mRNA in prostate cancer cells PC-3. Finally, we examined the molecular actions triggered by these analogs and found that their biological activity was related to their ability to induce expression and nuclear translocation of VDR and C/EBPβ.

Flow cytometric evaluation of intracellular cytokine synthesis in peripheral mononuclear cells of women with endometriosis.

Systemic changes related to cytokine expression levels in women with endometriosis remain a subject of controversy. There are many studies concerning this topic showing differential serum cytokine levels; however, there are limited data presenting cytokine expression at the single-cell level. This study focused on this question by measuring intracellular cytokine staining of activated peripheral CD3+ and CD14+ cells from women with endometriosis (investigative group) compared with those with uterine leiomyoma (control group). Isolated peripheral blood mononuclear cells from women with endometriosis and uterine leiomyoma were stimulated with PMA and ionomycin or with LPS to induce intracellular synthesis of TNF-alpha, IFN-gamma, and IL-8 in subpopulations of CD3+ cells and TNF-alpha, IL-6, IL-10, MCP-1, and IL-8 in CD14+ cells. Comparison of the total groups of patients showed no significant differences in any of the intracellular cytokines investigated in the T cells and monocytes of women with endometriosis compared with controls. When the group of women with endometriosis was divided with regard to severity of disease, a significantly lower percentage of CD3+CD8- lymphocytes stained for IFN-gamma and a significantly higher percentage of CD14+ cells stained for MCP-1 in advanced endometriosis patients compared with the control group were observed. We conclude that peripheral mononuclear cells in women with advanced endometriosis may have differential cytokine synthesis in vitro. These results support the idea that differing immune cell activity measured by intracellular cytokine profiles in women with advanced endometriosis may be more a consequence of the disease than a cause.

The Influence of Extracellular Matrix Proteins on T-cell Proliferation and Apoptosis in Women with Endometriosis or Uterine Leiomyoma

Problem:  Interactions between the extracellular matrix (ECM) and peripheral blood T cells in women with endometriosis and leiomyoma are hardly unknown. We have investigated the influence of two major ECM components, collagen IV (C‐IV) and fibronectin (Fn), on T‐cell proliferation and apoptosis in women with endometriosis and uterine leiomyoma. β1 integrin expression, responsible for interactions with ECM proteins, was also studied.

Matrix metalloproteinase (MMP)-2 and MMP-9 expression in tumor infiltrating CD3 lymphocytes from women with endometrial cancer.

Objective In this study, we hypothesized that not only endothelial malignant cells but also lymphocytes infiltrating tumor epithelium, in patients with endometrial cancer, could be an important source of the gelatinases (matrix metalloproteinase [MMP]-2 and MMP-9) extensive production, which in turn, may facilitate tumor cells infiltration and progression due to the extracellular matrix degradation. Materials and Methods First, we isolated lymphocytes from the endometrial carcinoma samples taken from 41 patients who were operated on and from healthy endometrial tissue taken of the same patients after histological verification. Then, we detected the level of CD3-positive cells in endometrial tissues by flow cytometry. Simultaneously, we studied the messenger RNA expression of MMP-2 and MMP-9 in the isolated cells from malignant and unchanged endometrial tissues. Using immunohistochemistry, we compared the protein expression of MMP-2, MMP-9, and CD3 in the studied samples. Results We showed the enhanced abundance of CD3 lymphocytes both by flow cytometry and immunohistochemistry in the samples from malignant tissues. The expression of MMP-9 in the endometrial carcinoma was increased significantly at the protein level but not at the messenger RNA level. We could not observe any differences concerning MMP-2 expression in both methods of detection. Conclusions CD-3 lymphocytes significantly infiltrate endometrial cancer tissue, but they do not seem to be the source of enhanced metalloproteinases 2 and 9 expression in the tumor environment. Still, owing to the immunohistochemistry staining, we could show the significant increase of MMP-9 protein in the very close vicinity of tumor-infiltrating CD3 lymphocytes. Could it be the result of CD3 lymphocyte action, or is it just the imperfection of the detecting method we used? This remains unclear. Further studies explaining the role of tumor infiltrating lymphocytes in mediating the endometrial cancer milieu are needed.