In vitro and in vivo Study of Cell Growth Inhibition of Simvastatin on Chronic Myelogenous Leukemia Cells

To evaluate anti-tumor effects of recombinant adenovirus p53, time-course p53, E6 expression, and cell growth inhibition were investigated in vitro and in vivo using cervical cancer cell lines such as CaSki, SiHa, HeLa, HeLaS3, C33A, and HT3. The cell growth inhibition was studied via cell count assay, MTT assay and neutral red assay. After transfecting AdCMVp53 into SiHa cells-xenografted nude mice, the transduction efficiency and anti-tumor effect were investigated for a month. The results showed that adenoviral p53 expression induced significant growth suppression on the cancer cells, in which E6 transcript was strongly repressed, and that the expression of p53 and E6 were remarkably dependent on each cell type. The transduction efficiency was highly maintained in vivo as well as in vitro, and the size of tumor was remarkably decreased in comparison with AdCMVLacZ control. The results suggest that the adenovirus-mediated p53 gene transfection was done very effectively in vitro and in vivo experiment, and the cell growth was suppressed via p53-dependent apoptotic cell death, and that the anti-tumor effect could be related to E6 and p53 expression pattern.

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A novel zinc-chelating small molecule exhibits cancer cell growth inhibition in vitro and in vivo by induction of tumor suppressors early growth response 1 (Egr-1) and Krüppel-Like Factor 4 (KLF4)

Journal of Clinical Oncology ◽

10.1200/jco.2007.25.18_suppl.14084 ◽

2007 ◽

Vol 25 (18_suppl) ◽

pp. 14084-14084

Author(s):

L. Lock ◽

A. Khine ◽

M. Huesca ◽

V. Lawson ◽

R. Peralta ◽

...

Keyword(s):

Gene Expression ◽

Transcription Factor ◽

Cell Growth ◽

Growth Inhibition ◽

Cancer Cell ◽

Phase Cell ◽

Cell Growth Inhibition ◽

Ht 29

14084 Background: Lead compound LT-253 was selected from a group of 2-indolyl imidazol [4,5-d] phenanthroline derivatives with anticancer activity. It shows potent and selective anti-proliferative activity against several human cancer types in vitro, and in vivo in xenograft mouse models of human colon carcinoma (HT-29) and non-small cell lung carcinoma (H460). Methods: The mechanism of cell growth inhibition of LT-253 was investigated in HT-29 colon cancer cells using the XTT cell proliferation assay, flow cytometry and apoptosis assays. In vitro and in vivo zinc chelation was determined by competition assays using fluorescent and chromophoric chelators. Gene expression studies were performed by human genome microarray analysis and confirmed by quantitative real- time PCR. The transcription factor activity profile of LT-253-treated cells was determined by a multiplex transcription factor array and electrophoretic mobility shift assays. The functional role of specific genes was evaluated by siRNA gene knock-down. Results: LT-253 functions as chelator of zinc in vitro, and of intracellular labile zinc in HT-29 cells. Moreover, LT-253-mediated HT-29 cell growth inhibition was reversed by zinc supplementation. Gene expression profiling confirmed sustained changes in zinc-sensitive genes such as metallothionine and several zinc transporters, but not copper-sensitive or iron-sensitive genes. LT-253 induces cancer cell growth inhibition primarily through G1/S phase cell cycle arrest. Gene expression and transcription factor activities of both Egr-1 and KLF4 are induced within 4 hr post LT-253 treatment. Moreover, increased expression of both Egr-1 and KLF4 is observed in LT-253-sensitive cancer cell lines of various origins. Importantly, Egr-1 and KLF4 gene knock-down by siRNA reversed the LT-253-mediated cell growth inhibition of HT-29 cells. Conclusion: Selective chelation of intracellular labile zinc pool by LT-253 triggers immediate induction of stress-responsive tumor suppressor Egr-1 and sustained induction of zinc-responsive tumor suppressor KLF4, leading to G1/S phase cell cycle arrest and inhibition of tumor growth. No significant financial relationships to disclose.

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