Project description:Cultured cancer cells exhibit substantial phenotypic heterogeneity when measured in a variety of ways such as sensitivity to drugs or the capacity to grow under various conditions. Among these, the ability to exhibit anchorage-independent cell growth (colony forming capacity in semisolid media) has been considered to be fundamental in cancer biology because it has been connected with tumor cell aggressiveness in vivo such as tumorigenic and metastatic potentials, and also utilized as a marker for in vitro transformation. Although multiple genetic factors for anchorage-independence have been identified, the molecular basis for this capacity is still largely unknown. To investigate the molecular mechanisms underlying anchorage-independent cell growth, we have used genome-wide DNA microarray studies to develop an expression signature associated with this phenotype. Using this signature, we identify a program of activated mitochondrial biogenesis associated with the phenotype of anchorage-independent growth and importantly, we demonstrate that this phenotype predicts potential for metastasis in primary breast and lung tumors. Keywords: c-Myc or v-Src retroviral vector-infected immortalized mouse embryonic fibroblasts. Expression data of c-Myc and v-Src transformed MEFs was used to validate an expression signature generated from human cultured breast cancer cell lines with anchorage-independent growth ability.
Project description:Cultured cancer cells exhibit substantial phenotypic heterogeneity when measured in a variety of ways such as sensitivity to drugs or the capacity to grow under various conditions. Among these, the ability to exhibit anchorage-independent cell growth (colony forming capacity in semisolid media), has been considered to be fundamental in cancer biology, because it has been connected with tumor cell aggressiveness in vivo such as tumorigenic and metastatic potentials, and also utilized as a marker for in vitro transformation. Although multiple genetic factors for anchorage-independence have been identified, the molecular basis for this capacity is still largely unknown. To investigate the molecular mechanisms underlying anchorage independent cell growth, we have used genome-wide DNA microarray studies to develop an expression signature associated with this phenotype. Using this signature, we identify a program of activated mitochondrial biogenesis associated with the phenotype of anchorage-independent growth and importantly, we demonstrate that this phenotype predicts potential for metastasis in primary breast and lung tumors. Keywords: Breast cancer cell lines with various colony-forming ability
Project description:Cultured cancer cells exhibit substantial phenotypic heterogeneity when measured in a variety of ways such as sensitivity to drugs or the capacity to grow under various conditions. Among these, the ability to exhibit anchorage-independent cell growth (colony forming capacity in semisolid media), has been considered to be fundamental in cancer biology, because it has been connected with tumor cell aggressiveness in vivo such as tumorigenic and metastatic potentials, and also utilized as a marker for in vitro transformation. Although multiple genetic factors for anchorage-independence have been identified, the molecular basis for this capacity is still largely unknown. To investigate the molecular mechanisms underlying anchorage independent cell growth, we have used genome-wide DNA microarray studies to develop an expression signature associated with this phenotype. Using this signature, we identify a program of activated mitochondrial biogenesis associated with the phenotype of anchorage-independent growth and importantly, we demonstrate that this phenotype predicts potential for metastasis in primary breast and lung tumors. Keywords: Breast cancer cell lines with various colony-forming ability To develop an expression signature reflecting the capacity for anchorage-independent cell growth, we first carried out colony formation assays with 19 breast cancer cell lines in suspension culture dish with methyl-cellulose containing media. Starting with 20,000 plated cells, five cell lines (MDA-MB-361, HCC38, ZR75, Hs578T and BT483) gave rise to less than 20 colonies, while 8 cell lines (MCF7, MDA-MB-231, BT20, SKBR3, MDA-MB-435s, T47D and BT474) showed formation of more than 500 colonies. The rest of the cell lines showed an intermediate phenotype in colony forming ability (20-200 colonies; HCC1143, HCC1806, HCC1428, MDA-MB-453, CAMA1, BT549 and MDA-MB-157). Among 19 cell lines, 11 cell lines have duplicates of expression data in a different batch. We removed the batch effect of this Affymetrix expression data using ComBat according to the instruction of http://statistics.byu.edu/johnson/ComBat/Abstract.html. Therefore, this dataset is a combined and standardized data that are originally RMA formatted.
Project description:Cultured cancer cells exhibit substantial phenotypic heterogeneity when measured in a variety of ways such as sensitivity to drugs or the capacity to grow under various conditions. Among these, the ability to exhibit anchorage-independent cell growth (colony forming capacity in semisolid media) has been considered to be fundamental in cancer biology because it has been connected with tumor cell aggressiveness in vivo such as tumorigenic and metastatic potentials, and also utilized as a marker for in vitro transformation. Although multiple genetic factors for anchorage-independence have been identified, the molecular basis for this capacity is still largely unknown. To investigate the molecular mechanisms underlying anchorage-independent cell growth, we have used genome-wide DNA microarray studies to develop an expression signature associated with this phenotype. Using this signature, we identify a program of activated mitochondrial biogenesis associated with the phenotype of anchorage-independent growth and importantly, we demonstrate that this phenotype predicts potential for metastasis in primary breast and lung tumors. Keywords: c-Myc or v-Src retroviral vector-infected immortalized mouse embryonic fibroblasts.
Project description:The ability of high-risk neuroblastoma to survive unfavorable growth conditions and multimodal therapy is hypothesized to result from a phenomenon known as reversible adaptive plasticity (RAP). RAP is a novel phenomenon enabling neuroblastoma cells to transition between a proliferative anchorage dependent (AD) state and a slow growing anoikis-resistant anchorage independent (AI) state. We used microarrays to investigate the global gene expression profiles in AD and AI cells, and to identify the differential expressed genes within signaling pathways contributing to the reversible adaptive plasticity between AD and AI cells.
Project description:Acquisition of independence from anchorage to the extracellular matrix is a critical event for onset and progression of solid cancers. To identify and characterize new genes conferring anchorage independence, we transduced MCF10A human normal breast cells with a retroviral cDNA expression library and selected them by growth in suspension. Microarray analysis targeted on library-derived transcripts revealed robust and reproducible enrichment, after selection, of cDNAs encoding the scaffolding adaptor Gab2. Gab2 was confirmed to strongly promote anchorage-independent growth when overexpressed. Interestingly, downregulation by RNAi of endogenous Gab2 in neoplastic cells did not affect their adherent growth, but abrogated their growth in soft agar. Gab2-driven anchorage independence was found to specifically involve activation of the Src-Stat3 signaling axis. A transcriptional “signature” of 205 genes was obtained from GAB2-transduced, anchorage-independent MCF10A cells, and found to contain two main functional modules, respectively controlling proliferation and cell adhesion/migration/invasion. Extensive validation on breast cancer datasets showed that the Gab2-signature provides a robust prognostic classifier for breast cancer metastatic relapse, largely independent from existing clinical and genomic indicators and from estrogen receptor status. This work highlights a pivotal role for GAB2 and its transcriptional targets in anchorage-independent growth and breast cancer metastatic progression.
Project description:The ability of high-risk neuroblastoma to survive unfavorable growth conditions and multimodal therapy is hypothesized to result from a phenomenon known as reversible adaptive plasticity (RAP). RAP is a novel phenomenon enabling neuroblastoma cells to transition between a proliferative anchorage dependent (AD) state and a slow growing anoikis-resistant anchorage independent (AI) state. We used microarrays to investigate the global gene expression profiles in AD and AI cells, and to identify the differential expressed genes within signaling pathways contributing to the reversible adaptive plasticity between AD and AI cells. Comparison of microarray data from AD cells (n=4 independent cultures) versus AI cells (n=4 independent cultures) were performed using Partek Genomics Suite 6.5. Differentially expressed genes with an FDR M-bM-^IM-$5% and a fold-change M-bM-^IM-%1.5 were selected for pathway analysis.
Project description:Self-sufficiency (autonomy) in growth signaling, the earliest recognized hallmark of cancer, is fuelled by the tumor cell’s ability to ‘secrete-and-sense’ growth factors; this translates into cell survival and proliferation that is self-sustained by auto-/paracrine secretion. Using breast cancer cells that are either endowed or inept in growth signaling autonomy, here we reveal how tumor cell autonomy impacts cancer progression. Autonomy is associated with enhanced molecular programs for stemness, immune evasiveness, and epithelial-mesenchymal plasticity (EMP) across the entire mesenchymal spectrum. Autonomy is both necessary and sufficient for anchorage-independent growth factor-restricted growth, resistance to anti-cancer drugs and metastatic progression. Transcriptomic and proteomic studies show that autonomy is associated with self-sustained EGFR/ERBB signaling, a required signal for re-epithelialization. A gene expression signature was derived (a.k.a., autonomy signature) which revealed that autonomy is induced in circulating tumor cells (CTCs), the precursor tumor cells that re-epithelialize to initiate metastases. Autonomy in CTCs tracks therapeutic response and prognosticates outcome. Autonomy is present during reversible (but not stable) EMT and requires EGFR/ERBB signaling. These data support a role for growth signaling autonomy in the blood-borne dissemination of human breast cancer.
Project description:Normal human diploid fibroblast (TIG-3) cells were infected with retroviruses containing the early region of simian virus 40 (SV40) and encoding the catalytic component of human telomerase (hTERT) and human c-Myc. The resultant transformed cells (TSM cells) gained a moderate ability to undergo anchorage-independent growth. TSM clones grown in three dimensional (3-D) culture were picked up and expanded in 2-D culture to obtain AIG-1 clones. This selection process was repeated three times to yield AIG-3 cells.