alitretinoin and Osteosarcoma

This study was designed to investigate whether nuclear receptor agonists can be used as potential differentiation therapy agents for human osteosarcoma.. Four osteosarcoma cell lines (143B, MNNG/HOS, MG-63, and TE-85) were treated with proliferator-activated receptor (PPAR)gamma agonists, troglitazone and ciglitazone, and a retinoid X receptor (RXR) ligand, 9-cis retinoic acid. The proliferation and induction of apoptosis in the treated cells were assessed, as was the induction of alkaline phosphatase, a differentiation marker of osteoblasts.. The expression of PPARgamma was readily detected in all tested osteosarcoma lines. On treatment with the PPARgamma and RXR ligands, all four osteosarcoma lines exhibited a significantly reduced proliferation rate and cell viability. Among the four lines, 143B and MNNG/HOS were shown to be more sensitive to ligand-induced apoptosis, as demonstrated by the Crystal Violet and Hoechst staining assays. Of the three tested ligands, troglitazone was shown to be the most effective in inducing cell death, followed by 9-cis retinoic acid. Moreover, a strong synergistic effect on the induction of cell death was observed when both troglitazone and 9-cis retinoic acid or ciglitazone and 9-cis retinoic acid were administered to osteosarcoma cells. Troglitazone was shown to effectively induce alkaline phosphatase activity, a well-characterized hallmark for osteoblastic differentiation.. Our findings suggest that PPARgamma and/or RXR ligands may be used as efficacious adjuvant therapeutic agents for primary osteosarcoma, as well as potential chemopreventive agents for preventing the recurrence and metastasis of osteosarcoma after the surgical removal of the primary tumors.

Topics: Alitretinoin; Antineoplastic Agents; Apoptosis; Cell Differentiation; Cell Division; Chromans; Dose-Response Relationship, Drug; Drug Synergism; Gene Expression Regulation, Neoplastic; HT29 Cells; Humans; Osteosarcoma; Receptors, Cytoplasmic and Nuclear; Receptors, Retinoic Acid; Retinoid X Receptors; RNA, Neoplasm; Thiazoles; Thiazolidinediones; Time Factors; Transcription Factors; Tretinoin; Troglitazone; Tumor Cells, Cultured

To determine differentiation and growth inhibition effects of retinoids on canine osteosarcoma cells.. 3 osteosarcoma cell lines established from osteosarcomas in dogs.. Osteosarcoma cells were incubated with various concentrations of all-trans-retinoic acid and 9-cis-retinoic acid or control medium, counted daily for 10 days, and evaluated for morphologic changes. Synthesis of DNA was measured by use of a cell proliferation ELISA. To analyze effect of retinoids on colony formation on plastic dishes, cells were cultured for 14 days, fixed, and stained; number of colonies was counted.. In a dose-dependent manner, both retinoids induced morphologic differentiation and growth inhibition in the 3 osteosarcoma cell lines and inhibited each cell's ability to form anchorage-dependent colonies.. Retinoids induced differentiation of osteosarcoma cells of dogs, resulting in altered expression of their malignant phenotype. Induction of differentiation by retinoids may have potential as an adjunctive treatment for osteosarcoma in dogs.

Topics: Alitretinoin; Animals; Antimetabolites; Antineoplastic Agents; Bone Neoplasms; Bromodeoxyuridine; Cell Division; DNA; Dog Diseases; Dogs; Dose-Response Relationship, Drug; Enzyme-Linked Immunosorbent Assay; Microscopy, Phase-Contrast; Osteosarcoma; Tretinoin; Tumor Cells, Cultured

The effect of two retinoids, all- trans and 9- cis retinoic acid, on the differentiation of three canine osteosarcoma cells (OOS, HOS, and POS) was examined using markers specifically expressed by phenotypic osteoblasts. Both retinoids induced morphologic differentiation in all the canine osteosarcoma cells. Retinoids enhanced cell flattening and spreading, as well as reduction in cell overlapping. Alkaline phosphatase (ALP) activity and ALP staining was enhanced in OOS, and HOS cells, but decreased in POS cells. These results may suggest that OOS and HOS cells have immature osteoblastic properties and POS cells have mature osteoblastic properties. Retinoids decreased osteocalcin production in all the osteosarcoma cells. They induced an increase in production of type I collagen in HOS and POS cells, but a decrease in OOS cells. These results indicate that retinoids induce differentiation of canine osteosarcoma cells, resulting in an altered expression of their malignant phenotype.

Topics: Alitretinoin; Alkaline Phosphatase; Animals; Antineoplastic Agents; Bone Neoplasms; Cell Differentiation; Collagen; Dog Diseases; Dogs; Osteocalcin; Osteosarcoma; Tretinoin; Tumor Cells, Cultured

Retinoids, all-trans-retinoic acid (ATRA) and 9-cis-retinoic acid (9-cis-RA), induced morphological changes and apoptosis-like cell death characterized by cell shrinkage, chromatin condensation and nuclear disintegration in three canine osteosarcoma cells, OOS, HOS and POS, at a concentration of 10(-5) M. Both retinoid receptors, RARs and RXRs, were identified in these cells. 9-cis-RA bound to both the RXRs and the RARs, whereas ATRA bound to only the RARs in these cells. Those results indicate that the induction of apoptosis in canine osteosarcoma cells may be mediated by the specific control of RARs and RXRs.

Topics: Alitretinoin; Animals; Apoptosis; Dog Diseases; Dogs; Osteosarcoma; Receptors, Retinoic Acid; Retinoid X Receptors; Transcription Factors; Tretinoin

To determine effects of all-trans and 9-cis retinoic acid (RA) on tumor growth and metastatic ability of canine osteosarcoma cells transplanted into athymic (nude) mice.. Forty-five 5-week-old female BALB/c nude mice.. 1 X 10(7) POS osteosarcoma cells were transplanted subcutaneously into the intrascapular region of mice. All-trans RA (3 or 30 microg/kg of body weight in 0.1 ml of sesame oil), 9-cis RA (3 or 30 mg/kg in 0.1 ml of sesame oil), or sesame oil (0.1 ml; control treatment) were administered intragastrically 5 d/wk for 4 weeks beginning 3 days after transplantation (n = 4 mice/group) or after formation of a palpable tumor (5 mice/group). Tumor weight was estimated weekly by measuring tumor length and width, and retinoid toxic effects were evaluated daily. Two weeks after the final treatment, mice were euthanatized, and number of mice with pulmonary metastases was determined.. Adverse treatment effects were not detected. Tumor weight was less in mice treated with either dose of 9-cis RA than in control mice, although this difference was not significant. Treatment with 30 mg of 9-cis RA/kg initiated after tumor formation significantly reduced the incidence of pulmonary metastasis, compared with the control group.. 9-cis RA decreased the incidence of pulmonary metastasis in nude mice transplanted with canine osteosarcoma cells and may be a potential adjunct therapy for treatment of osteosarcoma in dogs.

Topics: Alitretinoin; Animals; Antineoplastic Agents; Bone Neoplasms; Dog Diseases; Dogs; Female; Lung Neoplasms; Mice; Mice, Inbred BALB C; Mice, Nude; Neoplasm Metastasis; Neoplasm Transplantation; Osteosarcoma; Transplantation, Heterologous; Tretinoin; Tumor Cells, Cultured