Effects of Low- or Moderate-dose Whole Body-X-ray Radiation on the Immune System of C57BL/6 Mice / 임상소아혈액종양

PURPOSE: Increase in the use of diagnostic imaging or occupational exposure to radiation have brought upon concerns on the safety and biological effects of low- or moderate-dose radiation. However, limited information is available on the effects of low or moderate dose radiation on human health. METHODS: Using C57BL/6 mice, we aimed to evaluate the biological effects of low- and moderate-dose radiation on the immune system. X-rays was chosen as a radiation source and we analyzed complete blood counts, various lymphocyte subsets and various cytokine levels after single fraction x-ray exposure (0.1 Gy, 1 Gy). RESULTS: No significant changes in the immunologic parameter of C57BL/6 mice were observed after radiation, except LIX (a cytokine equivalent to human CXCL5), that showed higher level after 0.1 Gy radiation compared to the control. CONCLUSION: We observed that a single fraction of low or moderate dose of X-ray radiation does not cause significant changes in the immune system of C57BL/6 mice. Further studies are necessary to elucidate the mechanism underlying our results.

Transplantation of human umbilical cord blood CD34⁺ cells into the liver of newborn NOD/SCID/IL-2Rγ null (NSG) mice after busulfan conditioning

No abstract available.

Metformin displays in vitro and in vivo antitumor effect against osteosarcoma / 소아과

PURPOSE: Patients with unresectable, relapsed, or refractory osteosarcoma need a novel therapeutic agent. Metformin is a biguanide derivative used in the treatment of type II diabetes, and is recently gaining attention in cancer research. METHODS: We evaluated the effect of metformin against human osteosarcoma. Four osteosarcoma cell lines (KHOS/NP, HOS, MG-63, U-2 OS) were treated with metformin and cell proliferation was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Cell cycle progression and apoptosis were evaluated using flow cytometric analysis, and migration and wound healing assay were performed. Fourteen female Balb/c-nude mice received KHOS/NP cell grafts in their thigh, and were allowed access to metformin containing water (2 mg/mL) ad libitum. Tumor volume was measured every 3–4 days for a period of 4 weeks. RESULTS: Metformin had a significant antiproliferative effect on human osteosarcoma cells. In particular, metformin inhibited the proliferation and migration of KHOS/NP cells by activation of AMP-activated protein kinase and consequent inhibition of the mammalian target of rapamycin pathway. It also inhibited the proliferation of cisplatin-resistant KHOS/NP clone cells. Analysis of KHOS/NP xenograft Balb/c-nude models indicated that metformin displayed potent in vivo antitumor effects. CONCLUSION: Further studies are necessary to explore metformin's therapeutic potential and the possibilities for its use as an adjuvant agent for osteosarcoma.

Humanizing NOD/SCID/IL-2Rγnull (NSG) mice using busulfan and retro-orbital injection of umbilical cord blood-derived CD34+ cells

BACKGROUND: Humanized mouse models are still under development, and various protocols exist to improve human cell engraftment and function. METHODS: Fourteen NOD/SCID/IL-2Rγnull (NSG) mice (4‒5 wk old) were conditioned with busulfan and injected with human umbilical cord blood (hUCB)-derived CD34+ hematopoietic stem cells (HSC) via retro-orbital sinuses. The bone marrow (BM), spleen, and peripheral blood (PB) were analyzed 8 and 12 weeks after HSC transplantation. RESULTS: Most of the NSG mice tolerated the regimen well. The percentage of hCD45+ and CD19+ cells rose significantly in a time-dependent manner. The median percentage of hCD45+cells in the BM was 55.5% at week 8, and 67.2% at week 12. The median percentage of hCD45+ cells in the spleen at weeks 8 and 12 was 42% and 51%, respectively. The median percentage of hCD19+ cells in BM at weeks 8 and 12 was 21.5% and 39%, respectively (P=0.04). Similarly, the median percentage of hCD19+ cells in the spleen at weeks 8 and 12 was 10% and 24%, respectively (P=0.04). The percentage of hCD19+ B cells in PB was 23% at week 12. At week 8, hCD3+ T cells were barely detectable, while hCD7+ was detected in the BM and spleen. The percentage of hCD3+ T cells was 2‒3% at week 12 in the BM, spleen, and PB of humanized NSG mice. CONCLUSION: We adopted a simplified protocol for establishing humanized NSG mice. We observed a higher engraftment rate of human CD45+ cells than earlier studies without any significant toxicity. And human CD45+ cell engraftment at week 8 was comparable to that of week 12.

Epidermal Growth Factor Receptor: Is It a Feasible Target for the Treatment of Osteosarcoma? / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Features of epidermal growth factor receptor (EGFR) expression in osteosarcoma and in vitro efficacies of EGFR inhibitors against osteosarcoma cells were evaluated. MATERIALS AND METHODS: Thirty biopsy samples of osteosarcoma patients were retrospectively analyzed for EGFR protein expression by immunohistochemistry. Relationships between EGFR expression and clinicopathologic characteristics and treatment outcomes were evaluated. Four osteosarcoma cell lines were analyzed for EGFR and p-EGFR expression by western blotting. Efficacies of gefitinib and BIBW2992 on osteosarcoma cells were evaluated using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Tyrosine kinase domains in exons 18 to 21 were sequenced and gene expression analyses of EGFR and PTEN were performed in four osteosarcoma cell lines. RESULTS: EGFR protein was expressed in 27 (90%) samples (6 low, 12 intermediate, 9 high) and in three cell lines. Intermediate or high staining for EGFR was related to a tumor volume<150 mL (p<0.001) and histologic subtype other than osteoblastic type (p=0.03). However, EGFR expression was not associated with histologic response to preoperative chemotherapy or survival. Gefitinib and BIBW 2992 did not have any significant inhibitory effect on cell viabilities. DNA sequencing analysis revealed three osteosarcoma cell lines have single base changes at codon 2361 of exon 20 (G to A), without affecting translation results. Furthermore, no mutation was found to be associated with constitutive EGFR activation. CONCLUSION: In the present study, gefitinib and BIBW2992 were not effective against osteosarcoma cells. However, as osteosarcoma cells express EGFR, further studies are necessary to explore the potential of other therapeutic agents targeting EGFR.