Biochanin A can effectively suppress the proliferation of osteosarcoma and regulate the expression of BGLAP, BAX, and ATF3, which may act as the potential therapeutic targets of osteosarcoma.
Expression of Notch, CTNNB1, hairy and enhancer of split 1 (Hes1), Bcl-2, Runt-related transcription factor 2 (Runx2), and osteocalcin increased and that of miR-340, Bcl-2 interacting mediator of cell death (BIM), and Bcl-2 associated protein X (Bax) decreased in OS tissues.
Moreover, galangin enhanced the expression of osteoblast differentiation markers (collagen type I, alkaline phosphatase, osteocalcin and osteopontin) remarkably and elevated the alkaline phosphatase activity in human osteosarcoma cells.
For this purpose, we employed the human osteocalcin (OC) promoter, which had shown marked osteosarcoma specificity in promoter studies using different luciferase assays in osteosarcoma and non-osteosarcoma cell lines.
Endogenous osteocalcin mRNA was expressed and further enhanced by vitamin D(3) in all osteosarcoma and prostate cancer cell lines and human osteoblasts, but not in human fibroblasts.
We show that TRPS1 is expressed in osteosarcoma cells and upon induction of osteoblast differentiation in primary mouse bone marrow stromal cells and that TRPS1 regulates the expression of osteocalcin in both cell types.
In cotransfection experiments with an osteocalcin (OC) promoter construct, we confirmed that only RUNX2wt and RUNX2Delta7 could upregulate the OC promoter activity in the osteosarcoma cell line.
The human osteosarcoma cell line MG-63 was used to measure effects of these drugs on (i) intracellular calcium concentration ([Ca2+]i) using a microfluorometric technique, (ii) alkaline phosphatase and osteocalcin levels (EIA) and (iii) the expression of cox-2 mRNA (quantitative real time PCR).
Reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed that HOSM-1 cells, an osteosarcoma cell line established from human mandible, expressed mRNA for osteoblastic markers, such as alkaline phosphatase, osteonectin, osteocalcin and parathyroid hormone receptor, thus exhibiting an osteoblastic phenotype.
An 800-bp human OC (hOC) promoter-luciferase construct exhibited strong basal and vitamin D-induced activity in OC-positive human prostate and osteosarcoma cell lines.
Research in our laboratory has revealed that OC is expressed in several solid tumors, including osteosarcoma and ovarian, lung, brain, and prostate cancers.
Because the sequence of OC-derived hexapeptide (HP) is nearly identical to the E2 region of the oxytocin receptor (OTR), we set out to ascertain whether the HP interferes with the osteosarcoma (OS)-associated oxytocin (OT) system.
Despite normal or elevated levels of core-binding factor alpha-1 expression in most specimens, osteocalcin expression was low or undetectable in most cases of osteosarcoma (25 of 34) and myositis ossificans (4 of 5).
The ability of COS31 cells to produce tumors in nude mice (i.e. a small animal model) typical of canine osteosarcoma (i.e. a large animal model) with a similar pathological and biological behavior (e.g. alkaline phosphatase and osteocalcin positive immunostaining, osteoid production, rapid growth, and wide spread metastases) demonstrates the potential utility of COS31 cells as a in vitro and in vivo model system in the development of new strategies in the treatment of human osteosarcoma.
In vivo, nude mice with subcutaneous tumors of either human osteosarcoma (MG-63) or rat osteosarcoma (ROS) received three intratumoral injections of Ad-OC-TK (5 x 10(8) PFU) plus daily intraperitoneal ACV (40 mg/kg body weight) for 2 weeks in combination with five weekly bolus intraperitoneal MTX (87.5 mg/kg).
Evidence for modulation of osteocalcin containing gamma-carboxyglutamic acid residues synthesis by insulin-like growth factor-I and vitamin K2 in human osteosarcoma cell line MG-63.
The Ad-OC-TK virus plus ACV treatment appears to be highly selective in blocking the growth of both murine and human osteosarcoma cell lines in vitro and murine osteosarcoma in vivo.
In addition, the genomic action of each vitamin D compound was assessed in a rat osteosarcoma cell line (ROS 17/2.8) by measuring its ability to transactivate a gene construct containing the vitamin D response element of the osteocalcin gene linked to the growth hormone reporter gene.
To explore the potential role of osteoblasts in hematopoietic differentiation, we measured the mRNA accumulation, protein production, and secretion of hematopoietic growth factors by the nonmineralizing MG-63 and the mineralizing SaOS-2 human osteosarcoma cell lines. mRNA for the osteoblast-specific protein osteocalcin was well as granulocyte colony-stimulating factor (G-CSF), transforming growth factor-beta 1 (TGF-beta 1), and tumor necrosis factor-alpha (TNF-alpha) was produced by the MG-63 and SaOS-2 cells, like primary human cells, in the presence and absence of L-ascorbate and beta-glycerol phosphate.
Both osteosarcoma cell lines have retained major functions of normal osteoblasts; principally, the capacity to produce hematopoietic growth factors (including IL-6) and osteocalcin, a noncollagenic protein essential in the bone formation process.
1,25-dihydroxyvitamin D3 (1,25[OH]2D3), an active form of vitamin D3, stimulated OC secretion from the human osteosarcoma cell line MG-63 in a dose-dependent manner.
Finally, the differentiation state of the osteosarcoma cell lines was investigated via the bone differentiation markers alkaline phosphates and osteocalcin.