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Transcription profiling of human SCLC cell line set 2

ABSTRACT: RNA expression analysis was performed to compare patterns to sensitivity to BCL2 inhibitors (ABT-263). Overexpression of the prosurvival Bcl-2 family members (Bcl-2, Bcl-xL and Mcl-1) is commonly associated with tumor maintenance, progression and chemoresistance. We previously reported the discovery of ABT-737, a potent, small molecule Bcl-2 family protein inhibitor. A major limitation of ABT-737 is that it is not orally bioavailable. This may limit its use for chronic single agent treatment and the flexibility to dose in combination with parenteral chemotherapy. Here we report the discovery and biological properties of ABT-263, a potent, orally bioavailable Bad-like BH3 mimetic (K(i)'s of < 1 nM for Bcl-2, Bcl-xL and Bcl-w). The oral bioavailability of ABT-263 in preclinical animal models is 20% - 50%, depending on formulation. ABT-263 disrupts Bcl-2/Bcl-xL interactions with pro-death proteins (e.g., Bim) in cells leading to the initiation of apoptosis within 2 hr post-treatment. In human tumor cells, ABT-263 rapidly induces Bax translocation, cytochrome c release and subsequent programmed cell death. Oral administration of ABT-263 alone induces complete tumor regressions in xenograft models of small cell lung cancer and acute lymphoblastic leukemia. In xenograft models of aggressive B-cell lymphoma and multiple myeloma where ABT-263 exhibits modest or no single agent activity, it significantly enhances the efficacy of clinically relevant therapeutic regimens. These data provide the rationale for clinical trials evaluating ABT-263 in SCLC and B-cell malignancies. The oral efficacy of ABT-263 should provide dosing flexibility to maximize clinical utility as both a single agent and in combination with standard chemotherapeutic regimens. Experiment Overall Design: Naive cell lines were isolated in duplicate or triplicate (only a single for H69AR) to determine RNA expression pattern.

ORGANISM(S): Homo sapiens

SUBMITTER: Tse C

PROVIDER: S-ECPF-GEOD-10841 | biostudies-other | 2008 May

REPOSITORIES: biostudies-other

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Project description:Melanoma tumor antigen p97 or melanotransferrin (MTf) is an iron (Fe)-binding protein with high homology to serum transferrin. MTf is expressed at very low levels in normal tissues and in high amounts in melanoma cells. The over-expression of MTf in tumor cells was hypothesized to assist rapidly proliferating neoplastic cells with their increased Fe requirements. However, our recent characterization of the MTf knockout (MTf -/-) mouse demonstrated that MTf did not have an essential role in Fe metabolism. To understand the function of MTf, we utilized whole-genome microarray analysis to examine the gene expression profile of five models after modulating MTf expression. These models included two new stably transfected MTf hyper-expression models (SK-N-MC neuroepithelioma and LMTK- fibroblasts) and one cell type (SK-Mel-28 melanoma) where MTf was down-regulated by post-transcriptional gene silencing. These findings were compared to alterations in gene expression identified using the MTf -/- mouse. In addition, the changes identified from the gene array data were also assessed in a new model of MTf down-regulation in SK-Mel-2 melanoma cells. In the cell line models, MTf hyper-expression led to increased cellular proliferation, while MTf down-regulation resulted in decreased proliferation. Across all five models of MTf down- and up-regulation, we identified three genes modulated by MTf expression. These included ATP-binding cassette sub-family B member 5 (Abcb5), whose change in expression mirrored MTf down- or up-regulation. In addition, thiamine triphosphatase (Thtpa) and transcription factor 4 (Tcf4) were inversely expressed relative to MTf levels across all five models. The products of these three genes are involved in membrane transport, thiamine phosphorylation and cell proliferation/survival, respectively. This study identifies novel molecular targets directly or indirectly regulated by MTf and potential pathways involved in its function. These molecular targets could be involved, at least in part, to the role of MTf in modulating proliferation. Experiment Overall Design: To prepare a construct capable of generating hairpin siRNA specific for human MTf mRNA, the expression vector, pSilencer™ 3.1-H1 neo (Ambion, Texas, USA) was used. The vector was used to clone transgene of 66-bp that transcribe 19-mer double-stranded hairpin RNAs of the target gene. The transgene were specifically targeted to positions 2031-2049-bp in the MTf gene (Genbank Accession: NM_005929). Transfections of pS-MTf transgenes or pS-scrambled vectors into human SK-Mel-28 melanoma cells were performed with LipofectamineTM 2000 reagent (Invitrogen, Melbourne, Australia). Total RNA was isolated from the cells using TRIzol Reagent® (Sigma-Aldrich) according to the manufacturer’s protocol. Total RNA from the stably-transfected SK-Mel-28 melanoma cell lines were prepared and hybridized onto Human Genome U133 Plus 2.0 Array. The human GeneChip® U133 Plus 2.0 consists of greater than 47,000 transcripts and variants from over 38,500 well characterized human genes (Affymetrix, Santa Clara, CA).

Project description:Melanoma tumor antigen p97 or melanotransferrin (MTf) is an iron (Fe)-binding protein with high homology to serum transferrin. MTf is expressed at very low levels in normal tissues and in high amounts in melanoma cells. The over-expression of MTf in tumor cells was hypothesized to assist rapidly proliferating neoplastic cells with their increased Fe requirements. However, our recent characterization of the MTf knockout (MTf -/-) mouse demonstrated that MTf did not have an essential role in Fe metabolism. To understand the function of MTf, we utilized whole-genome microarray analysis to examine the gene expression profile of five models after modulating MTf expression. These models included two new stably transfected MTf hyper-expression models (SK-N-MC neuroepithelioma and LMTK- fibroblasts) and one cell type (SK-Mel-28 melanoma) where MTf was down-regulated by post-transcriptional gene silencing. These findings were compared to alterations in gene expression identified using the MTf -/- mouse. In addition, the changes identified from the gene array data were also assessed in a new model of MTf down-regulation in SK-Mel-2 melanoma cells. In the cell line models, MTf hyper-expression led to increased cellular proliferation, while MTf down-regulation resulted in decreased proliferation. Across all five models of MTf down- and up-regulation, we identified three genes modulated by MTf expression. These included ATP-binding cassette sub-family B member 5 (Abcb5), whose change in expression mirrored MTf down- or up-regulation. In addition, thiamine triphosphatase (Thtpa) and transcription factor 4 (Tcf4) were inversely expressed relative to MTf levels across all five models. The products of these three genes are involved in membrane transport, thiamine phosphorylation and cell proliferation/survival, respectively. This study identifies novel molecular targets directly or indirectly regulated by MTf and potential pathways involved in its function. These molecular targets could be involved, at least in part, to the role of MTf in modulating proliferation. Experiment Overall Design: Hyper-expression constructs of the human MTf cDNA was generated using the pCMV-Script® (Stratagene, La Jolla, CA) expression vector. The inserts were sequenced and confirmed against human MTf (Genbank Accession: NM_005929) using the public NCBI database. Transfections of pCMV-Script® transgenes/vectors into human SK-N-MC neuroepithelioma cells was performed with Lipofectin® reagent (Invitrogen, Melbourne, Australia) according to the manufacturer’s protocol. Total RNA was isolated from the cells using TRIzol Reagent® (Sigma-Aldrich) according to the manufacturer’s protocol. Total RNA from the stably-transfected SK-N-MC neuroepithelioma cell lines were prepared and hybridized onto Human Genome U133 Plus 2.0 Array. The human GeneChip® U133 Plus 2.0 consists of greater than 47,000 transcripts and variants from over 38,500 well characterized human genes (Affymetrix, Santa Clara, CA).

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Transcription profiling of human SCLC cell line set 2

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