Zoledronic acid inhibits the growth of leukemic MLL-AF9 transformed hematopoietic cells

Abstract

A leukemic in vitro model produced by transducing Cord Blood derived-hematopoietic CD34 þ cells with the MLL-AF9 translocation resulting in the oncogenic fusion protein, is used to assess for sensitivity to Zoledronic acid. These cells are practically immortalized and are of myeloid origin. Proliferation, clonogenic and stromal coculture assays showed that the MLL-AF9 cells were considerably more sensitive to Zoledronic acid than normal hematopoietic CD34 þ cells or MS-5 stromal cells. The MLL-AF9 cells were notably more inhibited by Zoledronic acid when cultured as colonies in 3 dimensions, requiring cell-cell contacts compared to suspension expansion cultures. This is coherent with the mechanism of action of Zoledronic acid inhibiting farnesyl diphosphate synthase which results in a block in prenylation of GTPases such that their role in the membrane is compromised for cell-cell contacts. Zoledronic acid can be proposed to target the MLL-AF9 leukemic stem cells before they emerge from the hematopoietic niche, which being in proximity to bone osteoclasts where Zoledronic acid is sequestered can be predicted to result in sufficient levels to result in an anti-leukemic action.

Cellular and Biochemical Characterization of Mesenchymal Stem Cells from Killian Nasal Polyp

“…The PCR cycling conditions included an initial denaturation of 95 °C for 3 min followed by 45 cycles of 95 °C for 10 s, 60 °C for 10 s, and 72 °C for 20 s, followed by a melting curve. All mRNA levels were normalized to GAPDH expression, and the relative gene expression was calculated using the comparative threshold cycle Ct method [ 61 ].…”

Enhanced ZNF521 expression induces an aggressive phenotype in human ovarian carcinoma cell lines

“…Analysis of gene expression was calculated as 2 −ddCt and normalized for the housekeeping gene (GAPDH). Primers used in this study were as follows (5'-3'): h-ZNF521 were previously described [50];…”

Regulatory Role of microRNAs Targeting the Transcription Co-Factor ZNF521 in Normal Tissues and Cancers

“…The overexpression of this protein sustains clonogenic growth, migration and tumorigenicity of medulloblastoma cells, and recently it was demonstrated to interact with GLI1 and GLI2 proteins stimulating the trans-activation of the Sonic Hedgehog pathway in medulloblastoma [25,26]. Zfp521 has also been implicated in the induction of B-cell lymphomagenesis [27] and is significantly overexpressed in many acute myeloid leukemias (AMLs), particularly in those transformed by the oncogenic fusion protein MLL-AF9, coherently in MLL-rearranged AML cell lines and primary ex vivo MLL-AF9 expressing cells, ZNF521 depletion blocks AML progression [28][29][30][31][32]. A feed forward loop of transcriptional activation has been proposed where MLL/AF9 transactivates ZNF521 in AML leukemia [32].…”