Roles of mTOR signal pathway in bone metastases from cancer / 中国肿瘤生物治疗杂志

@#超过25%的实体瘤患者在晚期都会出现不同程度的骨转移。发生骨转移的肿瘤细胞与骨微环境内细胞相互作用， 骨 稳态被打破，建立起促进肿瘤生长、加速骨质破坏的恶性循环，进一步促进肿瘤细胞在骨髓腔中浸润，导致转移的级联反应。肿 瘤骨转移是一个复杂的过程，大量分子和信号通路参与其中。研究证实，哺乳动物雷帕霉素靶蛋白（mammalian target of rapamycin, mTOR）信号通路活性的改变与肿瘤细胞的骨转移以及转移后骨质破坏密切相关。本文从肿瘤细胞的脱落、迁移、黏附和侵 入等转移步骤以及骨代谢变化两方面对mTOR信号通路在肿瘤骨转移过程中的作用进行阐述，为肿瘤骨转移的预防和治疗提供 新的方向。

HrpNEa-induced deterrent effect on phloem feeding of the green peach aphid Myzus persicae requires AtGSL5 and AtMYB44 genes in Arabidopsis thaliana.

Myzus persicae, a generalist phloem-feeding insect, develops with induced expression of the AtMYB44 gene. Special GLUCAN SYNTHESIS-LIKE (GSL) genes and β-1,3-glucan callose play an important role in plant defence responses to attacks by phloem-feeding insects. Here we report that AtGLS5 and AtMYB44 are both required for HrpNEainduced repression of M. persicae feeding from the phloem of Arabidopsis leaves. In 24 h successive surveys on large-scale aphid populations, the proportion of feeding aphids was much smaller in HrpNEa-treated plants than in control plants, and aphids preferred to feed from the 37 tested atgsl mutants rather than the wild-type plant. The atgsl mutants were generated previously by mutagenesis in 12 identified AtGSL genes (AtGSL1 through AtGSL12); in the 24 h survey, both atgsl5 and atgsl6 tolerated aphid feeding, and atgsl5 was the most tolerant. Consistently, atgsl5 was also most inhibitive to the deterrent effect of HrpNEa on the phloem-feeding activity of aphids as monitored by the electrical penetration graph technique. These results suggested an important role of the AtGSL5 gene in the effect of HrpNEa. In response to HrpNEa, AtGSL5 expression and callose deposition were induced in the wild-type plant but not in atgsl5. In response to HrpNEa, moreover, the AtMYB44 gene known to be required for repression of aphid reproduction on the plant was also required for repression of the phloem-feeding activity. Small amounts of the AtGSL5 transcript and callose deposition were detected in the atmyb44 mutant, as in atgsl5. Both mutants performed similarly in tolerating the phloem-feeding activity and impairing the deterrent effect of HrpNEa, suggesting that AtGSL5 and AtMYB44 both contributed to the effect.