Skip to Content
Merck
  • Expression of an estrogen-regulated variant transcript of the peroxisomal branched chain fatty acid oxidase ACOX2 in breast carcinomas.

Expression of an estrogen-regulated variant transcript of the peroxisomal branched chain fatty acid oxidase ACOX2 in breast carcinomas.

BMC cancer (2015-07-18)
Sunniva Stordal Bjørklund, Vessela N Kristensen, Michael Seiler, Surendra Kumar, Grethe I Grenaker Alnæs, Yao Ming, John Kerrigan, Bjørn Naume, Ravi Sachidanandam, Gyan Bhanot, Anne-Lise Børresen-Dale, Shridar Ganesan
ABSTRACT

Alternate transcripts from a single gene locus greatly enhance the combinatorial flexibility of the human transcriptome. Different patterns of exon usage have been observed when comparing normal tissue to cancers, suggesting that variant transcripts may play a role in the tumor phenotype. Ribonucleic acid-sequencing (RNA-seq) data from breast cancer samples was used to identify an intronic start variant transcript of Acyl-CoA oxidase 2, ACOX2 (ACOX2-i9). Difference in expression between Estrogen Receptor (ER) positive and ER negative patients was assessed by the Wilcoxon rank sum test, and the findings validated in The Cancer Genome Atlas (TCGA) breast cancer dataset (BRCA). ACOX2-i9 expression was also assessed in cell lines using both quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) and Western blot analysis. Knock down by short hairpin RNA (shRNA) and colony formation assays were used to determine whether ACOX2-i9 expression would influence cellular fitness. The effect of ACOX2-i9 expression on patient survival was assessed by the Kaplan-Meier survival function, and association to clinical parameters was analyzed using a Fisher exact test. The expression and translation of ACOX2-i9 into a 25 kDa protein was demonstrated in HepG2 cells as well as in several breast cancer cell lines. shRNA knock down of the ACOX2-i9 variant resulted in decreased cell viability of T47D and MDA-MB 436 cells. Moreover, expression of ACOX2-i9 was shown to be estrogen regulated, being induced by propyl pyrazoletriol and inhibited by tamoxifen and fulvestrant in ER+ T47D and Mcf-7 cells, but not in the ER- MDA-MB 436 cell line. This variant transcript showed expression predominantly in ER-positive breast tumors as assessed in our initial set of 53 breast cancers and further validated in 87 tumor/normal pairs from the TCGA breast cancer dataset, and expression was associated with better outcome in ER positive patients. ACOX2-i9 is specifically enriched in ER+ breast cancers where expression of the variant is associated with improved outcome. These data identify variant ACOX2 as a potential novel therapeutic biomarker in ER+ breast tumors.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Sodium dodecyl sulfate, ≥99.0% (GC), dust-free pellets
Supelco
Sodium dodecyl sulfate, dust-free pellets, suitable for electrophoresis, for molecular biology, ≥99.0% (GC)
Sigma-Aldrich
Monoclonal Anti-ACOX2, (C-terminal) antibody produced in mouse, clone 1A7, purified immunoglobulin, buffered aqueous solution
Sigma-Aldrich
Sodium chloride, BioPerformance Certified, ≥99% (titration), suitable for insect cell culture, suitable for plant cell culture
Sigma-Aldrich
Sodium chloride solution, 0.85%
Sigma-Aldrich
Sodium chloride-35Cl, 99 atom % 35Cl
Sigma-Aldrich
Sodium chloride, random crystals, optical grade, 99.9% trace metals basis
Sigma-Aldrich
Sodium dodecyl sulfate, ACS reagent, ≥99.0%
Sigma-Aldrich
Sodium chloride, BioUltra, for molecular biology, ≥99.5% (AT)
Sigma-Aldrich
Sodium dodecyl sulfate, ≥98.0% (GC)
Sigma-Aldrich
Sodium chloride, 99.999% trace metals basis
Sigma-Aldrich
Sodium chloride solution, 0.9% in water, BioXtra, suitable for cell culture
Sigma-Aldrich
Sodium chloride, BioReagent, suitable for cell culture, suitable for insect cell culture, suitable for plant cell culture, ≥99%
Sigma-Aldrich
Sodium dodecyl sulfate, BioXtra, ≥99.0% (GC)
Sigma-Aldrich
Sodium dodecyl sulfate, BioReagent, suitable for electrophoresis, for molecular biology, ≥98.5% (GC)
Sigma-Aldrich
Sodium dodecyl sulfate, ReagentPlus®, ≥98.5% (GC)
Sigma-Aldrich
Sodium chloride, for molecular biology, DNase, RNase, and protease, none detected, ≥99% (titration)
Sigma-Aldrich
Sodium chloride, BioXtra, ≥99.5% (AT)
Sigma-Aldrich
Sodium chloride solution, 5 M
Sigma-Aldrich
Sodium dodecyl sulfate, tested according to NF, mixture of sodium alkyl sulfates consisting mainly of sodium dodecyl sulfate
Sigma-Aldrich
Sodium dodecyl sulfate, ≥90% ((Assay))
Sigma-Aldrich
Sodium chloride, tablet
Sigma-Aldrich
Sodium chloride, meets analytical specification of Ph. Eur., BP, USP, 99.0-100.5%
Sigma-Aldrich
Sodium chloride solution, 5 M in H2O, BioReagent, for molecular biology, suitable for cell culture
Sigma-Aldrich
Sodium chloride solution, BioUltra, for molecular biology, ~5 M in H2O
Sigma-Aldrich
Sodium chloride, AnhydroBeads, −10 mesh, 99.999% trace metals basis
Sigma-Aldrich
Sodium dodecyl sulfate, 92.5-100.5% based on total alkyl sulfate content basis
SAFC
Sodium chloride solution, 5 M
Sigma-Aldrich
Sodium dodecyl sulfate, BioUltra, for molecular biology, ≥99.0% (GC)
Sigma-Aldrich
Sodium dodecyl sulfate, BioReagent, suitable for electrophoresis, for molecular biology, ≥98.5% (GC), free-flowing, Redi-Dri