Integrin β3-mediated Src activation regulates apoptosis in IEC-6 cells via Akt and STAT3
Integrin β3-mediated Src activation regulates apoptosis in IEC-6 cells via Akt and STAT3
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DOI：
10.1042/bj20060256
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发表时间：
2006-08-01
影响因子：
4.1
通讯作者：
Johnson, Leonard R.
中科院分区：
文献类型：
--
作者：
Bhattacharya, Sujoy;Ray, Ramesh M.;Johnson, Leonard R.
肠上皮（IEC-6）细胞在ODC（鸟氨酸脱羧酶）抑制和随后的多胺耗竭后对凋亡具有抗性。多胺的消耗迅速激活NF-κ B（核因子KB）和STAT 3（信号转导和转录激活因子3），这是观察到的细胞凋亡减少的原因。由于NF-κ B和STAT 3信号通路都可以被Src激酶激活，我们研究了它在抗凋亡反应中的作用。DFMO（α-二氟甲基鸟氨酸）抑制ODC在30分钟内增加了Src和ERK 1/2（细胞外信号调节激酶1/2）的活性，这是由外源性多胺添加到含DFMO的培养基中所阻止的。相反，表皮生长因子介导的Src和ERK 1/2激活并没有阻止通过添加多胺。用PP 2 {4-氨基-5-（4-氯苯基）-7-（叔丁基）吡唑并[3，4-d]嘧啶}和DN-Src（显性负性Src）构建体抑制Src阻止了Akt、JAK（Janus激酶）和STAT 3的活化。DN-Src表达细胞的自发凋亡增加，多胺耗尽的保护作用消失。DFMO消耗多胺增加了整合素β 3 Tyr（785）磷酸化。与塑料相比，铺在纤连蛋白上的细胞具有显著更高的β 3磷酸化和Src活化。添加到纤连蛋白基质中的外源多胺阻止了Src的激活。Arg-Gly-Asp-Ser抑制β 3、Src和Akt磷酸化，并使多胺耗竭的细胞对肿瘤坏死因子α/环己酰亚胺介导的凋亡敏感。纤连蛋白激活Src，随后保护细胞免于凋亡。总之，这些结果表明，抑制ODC快速去除了一小部分可利用的多胺，从而触发β 3整联蛋白的活化，进而活化Src。随后的Akt和JAK激活伴随着NF-κ B和STAT 3易位到细胞核以及抗凋亡蛋白的合成。
Intestinal epithelial (IEC-6) cells are resistant to apoptosis following the inhibition of ODC (ornithine decarboxylase) and subsequent polyamine depletion. The depletion of polyamines rapidly activates NF-kappa B (nuclear factor KB) and STAT3 (signal transducer and activator of transcription 3), which is responsible for the observed decrease in apoptosis. Since both NF-kappa B and STAT3 signalling pathways can be activated by Src kinase, we examined its role in the antiapoptotic response. Inhibition of ODC by DFMO (alpha-difluoromethylornithine) increased the activity of Src and ERK1/2 (extracellular-signal-regulated kinase 1/2) within 30 min, which was prevented by exogenous polyamines added to the DFMO-containing medium. Conversely, epidermal growth factor-mediated Src and ERK1/2 activation was not prevented by the addition of polyamines. Inhibition of Src with PP2 {4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d] pyrimidine} and a DN-Src (dominant-negative Src) construct prevented the activation of Akt, JAK (Janus kinase) and STAT3. Spontaneous apoptosis was increased in DN-Src-expressing cells and the protective effect of polyamine depletion was lost. Polyamine depletion by DFMO increased integrin beta 3 Tyr(785) phosphorylation. Cells plated on fibronectin had significantly higher beta 3 phosphorylation and Src activation compared with plastic. Exogenous polyamines added to the fibronectin matrix prevented Src activation. Arg-Gly-Asp-Ser inhibited beta 3, Src and Akt phosphorylation and sensitized polyamine-depleted cells to tumour necrosis factor alpha/cycloheximide-mediated apoptosis. Fibronectin activated Src and subsequently protected cells from apoptosis. Together, these results suggest that the inhibition of ODC rapidly removes a small pool of available polyamines triggering the activation of beta 3 integrin, which in turn activates Src. The subsequent Akt and JAK activation is accompanied by translocation of NF-kappa B and STAT3 to the nucleus and the synthesis of antiapoptotic proteins.