Tehran University Medical Journal

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Background: Bone Marrow Transplantations (BMT) are limited by low CD34+ cell counts in umbilical cord blood (UCB) and these cells need to be expanded for success in such procedures. To achieve this goal, ex vivo expansion of hematopoietic stem cells (HSCs) by enhancing their self-renewal activity on demineralized bone matrix (DBM) scaffold coated with mesenchymal progenitor cells (MPCs) and unrestricted somatic stem cells (USSCs) was recommended. TGF-b pathway is a key inhibitory factor for HSCs self-renewal. In this study ex vivo expansion and downregulation of TGF-b pathway were simultaneously performed.

Methods: USSC cells were isolated from UCB and then coated on DBM scaffold as a feeder layer. UCB CD34+ cells were isolated from UCB by magnetic activated cell sorting (MACS) method and were transfected by siRNA against TGFbR2 in two-dimensional (2D) and three-dimensional (3D) cultures by co-cultivation with USSC. TGFbR2 expression levels were evaluated by quantitative real-time PCR. Cell count and flow cytometry were performed and clonogenic activity was evaluated.

Results: Ex vivo expansion of CD34+ cells was significantly enhanced (41±0.7 folds) by TGFbR2 downregulation, especially in 2D than 3D cultures. Finally, 2D culture showed less TGFbR2 expression levels and higher increase in the percentage of CD34 markers by flow cytometry assay.

Conclusion: The 3D siRNA delivery system would be of lower efficiency in contrast to 2D settings where the cells have less freedom and are in more contact with the feeder layer.

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Background: Metastasis associated miRNA (metastamiR) opened a new field of anti-metastatic therapy which have a great potential of treatment for the most lethal aspect of cancer, metastasis. The pleiotropic nature of gene regulation exhibited by certain miRNAs that showed that miRNAs might be endowed with a capacity to function as crucial modulators of tumor metastasis. MiR-31 is a pleiotropic anti-metastatic miRNA whose expression decreased significantly in metastatic breast cancer cells. MiR-31 has multiple roles in metastasis cascade. Therefore, using the miR-31-restoration based therapy could be an efficient anti-metastatic strategy for cancer therapy. Methods: This research was performed from May 2014 to October 2015 in Tarbiat Modares University in Tehran, Iran. The double-strand oligo of mature miR-31 was cloned into pcDNA 6.2gw/EmGFP according to the manufacturer instruction. The MDA-MB231, MCF-7 breast cancer cell lines were cultured and their miRNAs have been extracted. The expression of miR-31 has been quantified by Real time-PCR be-fore transfection of construct contained miR-31 into two cell lines and in normal breast cells. Then the constructs contain miR-31 have been transfected in to two cell lines. The expression of miR-31 has been quantified after 48 hours. Scratch and invasion as-say have been carried out for assessing the level of migration and invasion. Results: The result of Real time-PCR before transfection of constructs contained miR-31 have been shown 4 fold and more than 100 fold reduction in expression of miR-31 in MCF-7 and MDA-MB231 respectively in comparison to miR-31 expression in nor-mal breast cells, but after transfection of miR-31 construct to MDA-MB231 the quan-tification of expression showed the significant increase in mir-31 expression and 20 fold reduction in invasive and 10 fold reduction in migratory characteristics of MDA-MB231 in comparison to MCF-7. Conclusion: Metastasis associated miRNA have been represented a promising candi-dates in the field of anti-metastatic therapy and miR-31 as a powerful member of this family can function very effectively in order to inhibit the metastasis and introduce the new possibility of metastasis inhibition.