Evaluation of inhibitory effect of tumor vaccine in colon carcinoma model mice / 中国生物制品学杂志

Objective@#To evaluate the inhibitory effect of tumor vaccines in colon carcinoma model mice.@*Methods@# Mouse bone marrow⁃derived dendritic cells（BMDCs）were stimulated by using CpG β⁃glucan nanoparticles（CNP）in vitro. The BMDCs were divided into PBS group，NP group（without CpG nanoparticles），Lysate group（MC38 cell lysate）and CpG group（CpG1826），which were determined for the expression of marker molecules on the surface by flow cytometry and for the contents of interleukin⁃6（IL⁃6）and IL⁃12p40 in the culture supernatant by ELISA. The tumor lysate nano⁃vaccine was pre⁃ pared by mixing 50 mg／mL tumor lysate（MC38 cell lysate）with 200 mg／mL CNP in a volume ratio of 1∶1，with which mice were subcutaneously immunized as Vaccine group. Vaccine group，PBS group，CNP group and Lysate group were im⁃ munized once a week，for three times in total. Mice were subcutaneously inoculated with MC38 cells，2 × 105 cells for each， in the right lower limb 1 h after the last immunization，and measured for tumor volume once every three days to plot the tumor growth curve. The ratios of CD3+ CD4+ T and CD3+ CD8+ T cells in the blood were analyzed by flow cytometry and the levels of tumor necrosis factor⁃α（TNF⁃α）and interferon γ（IFNγ）in the blood and spleen of mice were determined by ELISA.@*Results@# CNP effectively increased the expression of CD11c+ CD80+，CD11c+ CD86+，CD11c+ MHC⁃Ⅱ+ and the secretion of IL⁃6 and IL⁃12p40 in BMDCs in vitro，which were significantly higher than those in other 4 groups（t = 4. 3 ~ 46. 2，each P < 0. 05）. Compared with that of the other three groups，the tumor volume of mice in Vaccine group decreased significantly（t =2.6~3.4，eachP <0. 05）；TherewasnosignificantdifferenceinCD3+ CD8+ TandCD3+ CD8+ Tcellratios（t = 0.5~ 1. 9，each P > 0. 05）；The content of IFNγ in blood increased significantly（t = 3. 8 ~ 4. 6，P < 0. 05），while thatof TNF⁃α showed no significant difference（t = 0. 4 ~ 2. 0，each P > 0. 05）；However，the contents of IFN γ and TNF⁃α in spleen increased significantly（t = 6. 3 ~ 13. 0，each P < 0. 001）.@*Conclusion@#The prepared nano⁃vaccine of tumor lysate improvedtheimmune level in mice and effectively inhibited the growth of colon carcinoma.

Inhibition of protein kinase C activity inhibits osteosarcoma metastasis.

INTRODUCTION: For some cancers bone is the preferred site for metastasis and involves a cascade involving transition of epithelial cells to mesenchymal cells and subsequent intravasation to the blood and lymph vessels, and finally hematogenous dissemination to perivascular niches of the bone marrow sinusoids. It has been shown that protein kinase C can aid metastasis to bone. Hence, pharmacological inhibition of protein kinase C (PKC) activity is thought of as a potential therapeutic option in bone metastatic lesions. The objective of the current study was to investigate how PKCs exert their effect on bone cancer metastasis and to test the efficacy of pharmacological inhibition of PKC on bone metastasis. MATERIAL AND METHODS: The effect of the PKC inhibitor Go6983 on epithelial and mesenchymal cell marker expression in the osteosarcoma cell line DAN was determined by immunoblot and immunofluorescence analysis. The in vivo effect of Go6983 was evaluated with a xenograft model using DAN cells. RESULTS: Treatment with transforming growth factor ß (TGF-ß) led to loss of the epithelial cell marker and gain of mesenchymal cell markers in the osteosarcoma cell line, DAN. This transition occurred concomitantly with PKC activation. TGF-ß-mediated PKC activation resulted in activation of ribosomal protein 6 (S6), but not S6K1. Pharmacological inhibition of PKC activation attenuated these effects. In a xenograft model of experimental metastasis, pharmacological inhibition of PKC activation over a period of 4 weeks reduced both tumor burden and metastasis to lungs. CONCLUSIONS: Our results indicate that PKC potentiates tumor metastasis to the bone by potentiating translation increase and can be putatively inhibited by pharmacological inhibition.

The anti-cancer activity of the mTORC1/2 dual inhibitor XL388 in preclinical osteosarcoma models.

In the present study, we investigated the activity of XL388, a novel mammalian target of rapamycin (mTOR) complex 1/2 (mTORC1/2) dual inhibitor, in preclinical osteosarcoma (OS) models. XL388 was cytotoxic, cytostatic and pro-apoptotic to multiple established OS cell lines and primary human OS cells. XL388 blocked mTORC1/2 activation and downregulated cyclin D1/B1 expressions in OS cells, leaving AKT Thr-308 phosphorylation un-affected. Intriguingly, AKT1 T308A mutation potentiated XL388-induced cytotoxicity in OS cells. XL388 activated cytoprotective autophagy in OS cells. Autophagy inhibition, either pharmacologically or genetically, augmented XL388-induced anti-OS activity. Further, XL388 oral administration inhibited U2OS xenografts growth in severe combined immuno-deficient (SCID) mice. Such activity was enhanced with co-administration of the autophagy inhibitor 3-methyladenine (3-MA). Similarly, Beclin-1-silenced U2OS xenografts were remarkably more sensitive to XL388. Thus, concurrent blockage of mTORC1/2 with XL388 may have therapeutic value for OS.

Activity of the novel dual phosphatidylinositol 3-kinase/mammalian target of rapamycin inhibitor NVP-BEZ235 against osteosarcoma.

Recent studies have identified that constitutively active phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling is an important feature of osteosarcoma, where it promotes cell proliferation, survival, and chemo-resistance. Here, we studied the therapeutic potential of NVP-BEZ235, a novel dual PI3K/mTOR dual inhibitor, on osteosarcoma cells in vivo and in vitro. NVP-BEZ235 was cytotoxic and cytostatic to a panel of osteosarcoma lines (MG-63, U2OS and SaOs-2), where it induce apoptosis and cell-cycle arrest. At the molecular level, NVP-BEZ235 inhibited PI3K-AKT-mTORC1 activation and downregulated cyclin D1/cyclin B1 expressions, while increasing MEK/Erk phosphorylation in osteosarcoma cells. MEK/Erk inhibitors PD98059 and MEK-162 increased NVP-BEZ235 activity on osteosarcoma cells. In vivo, oral NVP-BEZ235 inhibited U2OS xenograft in SCID mice, and its anti-tumor efficiency was further enhanced by MEK-162 co-administration. Taken together, our findings indicate that dual inhibition of PI3K and mTOR with NVP-BEZ235, either alone or in combination with MEK/Erk inhibitors, may be an efficient treatment for osteosarcoma.

Bufotalin-induced apoptosis in osteoblastoma cells is associated with endoplasmic reticulum stress activation.

The search for novel and more efficient chemo-agents against malignant osteoblastoma is important. In this study, we examined the potential anti-osteoblastoma function of bufotalin, and studied the underlying mechanisms. Our results showed that bufotalin induced osteoblastoma cell death and apoptosis in dose- and time-dependent manners. Further, bufotalin induced endoplasmic reticulum (ER) stress activation in osteoblastoma cells, the latter was detected by the induction of C/EBP homologous protein (CHOP), phosphorylation of inositol-requiring enzyme 1 (IRE1) and PKR-like endoplasmic reticulum kinase (PERK), as well as caspase-12 activation. Conversely, the ER stress inhibitor salubrinal, the caspase-12 inhibitor z-ATAD-fmk as well as CHOP depletion by shRNA significantly inhibited bufotalin-induced osteoblastoma cell death and apoptosis. Finally, by using a mice xenograft model, we demonstrated that bufotalin inhibited U2OS osteoblastoma cell growth in vivo. In summary, our results suggest that ER stress contributes to bufotalin-induced apoptosis in osteoblastoma cells. Bufotalin might be investigated as a novel anti-osteoblastoma agent.

Anatomic and radiological study on posterior pedicle screw fixation in the atlantoaxial vertebrae of children.

OBJECTIVE: To investigate the feasibility of posterior fixation with 3.5-mm pedicle screws in the atlantoaxial vertebrae of children. METHODS: In this study, atlantoaxial vertebrae specimens were obtained from 10 cadavers of children aged 6-8 years. We measured the height and width of the C(1) pedicle and the midportion of C(1) lateral mass; the width of C(1) posterior arch under the vertebral artery groove and the height of the external and internal one-third of this part; the external, internal height and the superior, middle, inferior width of the C(2) pedicle (transverse foramen). Furthermore, computed tomography (CT) axial scan was performed on 20 age-matched volunteers to obtain relative data of their atlantoaxial vertebrae. We measured the length and width of the C(1) and C(2) pedicles in the atlantoaxial cross-sectional plane. On CT workstation, we also measured the angles between the longitudinal axes of the atlantoaxial pedicles and the midsagittal plane. RESULTS: For the cadaveric specimen group, the height and width of the C1 pedicle were (5.26+/-0.44) mm and (6.26+/-0.75) mm respectively. The height of the medial one-third of the C1 posterior arch under the vertebral artery groove was (4.07+/-0.24) mm. The external, internal height and superior, middle, inferior width of the C2 pedicle was (6.86+/-0.48) mm, (6.67+/-0.49) mm, (6.63+/-0.61) mm, (5.41+/-0.39) mm and (3.71+/-0.30) mm, respectively. For the volunteer group measured by CT scan, the height and width of the C(1) pedicle were (5.47+/-0.34) mm and (6.63+/-0.54) mm respectively, while (6.59+/-0.51) mm and (5.13+/-0.42) mm of the C2 pedicle. The angles between the atlas, axis pedicles and the midsagittal plane were (9.60+/-1.32) degree and (27.80+/-2.22) degree respectively. CONCLUSION: It is feasible to place a 3.5-mm pedicle screw in the C(1) and C(2) pedicles of children aged 6-8 years old.