Project description:Serum alkaline phosphatase (ALP) concentration is a prognostic factor for osteosarcoma in multiple studies, though its biological significance remains incompletely understood. To determine whether gene expression patterns differed in osteosarcoma from patients with differing serum ALP concentrations, microarray analysis was performed on 18 primary osteosarcoma samples and six osteosarcoma cell lines from dogs with normal and increased serum ALP concentration. No differences in gene expression patterns were noted between tumors or cell lines with differing serum ALP concentration using a gene-specific two-sample t-test. Using a more sensitive empirical Bayes procedure, DCUN1D1 was increased in both the tissue and cell lines of the normal ALP group. Using QPCR, differences in DCUN1D1 expression between the two groups failed to reach significance. The homogeneity of gene expression patterns of osteosarcoma associated differing serum ALP concentrations are consistent with previous studies suggesting serum ALP concentration is not associated with intrinsic differences of osteosarcoma cells. A total of 18 canine primary osteosarcoma tumor samples were used in this study. 9 tumor samples were from patients having a normal serum alkaline phosphatase concentration. 9 tumor samples were from patients having an increased serum alkaline phosphatase concentration. There were no reference tissues or controls used in this study.
Project description:An increased serum alkaline phosphatase concentration is known to be associated with a negative prognosis in canine and human osteosarcoma. To expand upon previous studies regarding the biological relevance of increased serum alkaline phosphatase as a negative prognostic factor, xenogeneic heterotopic transplants were performed using six canine primary osteosarcoma cell lines generated from patients with differing serum alkaline phosphatase concentrations (3 normal and 3 increased). Three of the six cell lines were capable of generating tumors and tumor formation was independent of the serum alkaline phosphatase status of the cell line. Microarray analysis identified 379 genes as being differentially-expressed between the tumorigenic and non-tumorigenic cell lines. Frizzled-6 was up-regulated to the greatest extent (7.78 fold) in tumorigenic cell lines compared to non-tumorigenic cell lines. Frizzled-6, a co-receptor for Wnt ligands has been associated with enhanced tumor-initiating cells and poor prognosis for other tumors. The increased expression of frizzled-6 was confirmed by QPCR and Western blot analysis. Additionally, the tumorigenic cell lines also had an increase in the percentage of side population cells compared to non-tumorigenic cell lines (5.89% versus 1.58%, respectively). There were no differences in tumorigenicity, frizzled-6, or percentage of side population cells noted between osteosarcoma cell lines generated from patients of differing serum alkaline phosphatase concentration. However, to our knowledge this is the first study to identified frizzled-6 as a possible marker of osteosarcoma cell populations with enhanced tumorigenicity and side population cells. Future work will focus on defining the role of frizzled-6 in osteosarcoma tumorigenesis and tumor-initiating cells. A total of six canine primary osteosarcoma cell lines were used in this study. Three cell lines were capable of forming tumors when transplanted into mice (tumorigenic) and three cell lines were not capable of forming tumors upon transplant into mice (non-tumorigenic). The gene expression data is from the primary cell lines, not the transplanted cells. There were no reference cell lines or controls used in this study.
Project description:An increased serum alkaline phosphatase concentration is known to be associated with a negative prognosis in canine and human osteosarcoma. To expand upon previous studies regarding the biological relevance of increased serum alkaline phosphatase as a negative prognostic factor, xenogeneic heterotopic transplants were performed using six canine primary osteosarcoma cell lines generated from patients with differing serum alkaline phosphatase concentrations (3 normal and 3 increased). Three of the six cell lines were capable of generating tumors and tumor formation was independent of the serum alkaline phosphatase status of the cell line. Microarray analysis identified 379 genes as being differentially-expressed between the tumorigenic and non-tumorigenic cell lines. Frizzled-6 was up-regulated to the greatest extent (7.78 fold) in tumorigenic cell lines compared to non-tumorigenic cell lines. Frizzled-6, a co-receptor for Wnt ligands has been associated with enhanced tumor-initiating cells and poor prognosis for other tumors. The increased expression of frizzled-6 was confirmed by QPCR and Western blot analysis. Additionally, the tumorigenic cell lines also had an increase in the percentage of side population cells compared to non-tumorigenic cell lines (5.89% versus 1.58%, respectively). There were no differences in tumorigenicity, frizzled-6, or percentage of side population cells noted between osteosarcoma cell lines generated from patients of differing serum alkaline phosphatase concentration. However, to our knowledge this is the first study to identified frizzled-6 as a possible marker of osteosarcoma cell populations with enhanced tumorigenicity and side population cells. Future work will focus on defining the role of frizzled-6 in osteosarcoma tumorigenesis and tumor-initiating cells.