白介素33促進(jìn)低轉(zhuǎn)移肺癌細(xì)胞在缺營養(yǎng)環(huán)境下脹亡

1、Interleukin-33 enhances programmed oncosis of ST2L-positive low-metastatic cells in the tumour microenvironment of lung cancer脹亡( oncosis)脹亡：細(xì)胞腫脹和核溶解的細(xì)胞損傷過程脹亡的形態(tài)學(xué)特征 脹亡細(xì)胞的形態(tài)學(xué)表現(xiàn)為細(xì)胞腫脹,體積增大,胞漿空泡化,胞漿內(nèi)出現(xiàn)致密顆粒,內(nèi)質(zhì)網(wǎng)腫脹,線粒體早期可出現(xiàn)致密化,后期腫脹,絮狀改變或出現(xiàn)高致密顆粒,嵴破壞; 細(xì)胞腫脹波及核,核內(nèi)染色質(zhì)分散,凝集在核膜、核仁周圍,有時聚集成團(tuán)塊;胞膜起泡是脹亡早期事件,隨之胞膜通透性增加,

2、胞膜崩解。 脹亡細(xì)胞后期往往表現(xiàn)為核溶解,由于胞內(nèi)容物外溢,脹亡細(xì)胞周圍有明顯炎癥反應(yīng)Interleukin-33 (IL-33), Interleukin-33 (IL-33), a member of the IL-1 cytokine family, is a natural ligand for the IL-33 receptor, which is a heterodimer composed of ST2L and the IL-1 receptor accessory protein (IL-1RAcP).13 IL-33 is primarily expressed in e

3、pithelial cells and endothelial cells as a proinflammatory cytokine. IL-33 is usually localised in the cell nucleus as an alarmin that signals to local immune cells in response to tissue damage caused by injury,necrosis or exposure to pathogensIL-33 polarises naiveT cells to produce Th2-associated c

4、ytokines, it strongly induces proinflammatory cytokine and chemokine production by mast cells and eosinophils, and it stimulates the polarisation of alternatively activated M2 macrophagesIL-33 has an important role in Th2 immunity and Th2-related diseasesST2L is expressed on the cell surface of Th2

5、cells, but not of Th1 cells,and on the cell surface of other immune-related cells including NK and NKT cellsST2 and IL-33 expression in human lung cancers and pulmonary alveolar cellsST2 mRNA was found to be significantly downregulated in lung cancers irrespective of histological typesSurvival analy

6、sis in PrognoScan database also revealed that the ST2 expression level was inversely correlated with relapsefreesurvival and overall survivalIL-33 mRNA was significantly downregulated in lung cancers, inversely correlating with the malignancy indexIL-33 was detected in the nuclei of HPAEpiCs , indic

7、ating its role as an alarmin in these cells.qRT-PCR analysis revealed that ST2L, sST2, asecreted soluble ST2 that acts as a decoy receptor for IL-33,IL-1RAcP, MyD88 and IL-33 were expressed in HPAEpiCs,whereas those genes were significantly downregulated inA549 cellsAmong 10 cell lines, only PC-14 a

8、denocarcinoma cells expressed a substantial amount of ST2L mRNA. However, these cells did not express IL-1RAcPmRNAThus, none of the human lung cell lines that have been examined thus far expressed functional ST2Llow-metastatic cells (P29and P34) derived from 3LL expressed ST2L, whereas the high-meta

9、static cells (D6 and A11) only slightly expressedST2L . P29 and P34 cells also expressed IL-1RAcP and MyD88IL-33-presenting cells in 3LL tumoursThe IL-33 immunofluorescencewas stronger, and the number of the IL-33+ cells per mm2 was larger in P29 tumours in B6 mice than those in IL-33 /miceIL-1 pote

10、ntly induced IL-33 mRNA expression in P29 cells in a time- and dose-dependent mannerNone of the cytokines induced IL-33 expression in A11 cellsWe therefore consider that intratumoural IL-1 and IL-33 is primarily responsible for IL-33 expression in P29tumours. However, at present, we cannot explain t

11、he reason why not all P29 cells in the tumours expressed IL-33.rIL-33 enhances the death of the low-metastatic 3LL cells under nutrient-depleted and hypoxic/anoxic conditionsrIL-33 enhanced the death of P29 and P34 cells, but not of D6 and A11 cells, in low-glucose (0.1 g/l glucose) medium (GlucL) i

12、n a dose- and time-dependent mannerThese ST2L knockdown cells were refractory torIL-33-induced cell death in GlucL mediumP29 cells transfected with MyD88 small-interfering RNA (siRNA) also displayed resistance to rIL-33These results indicate that IL-33 augments the death of P29 cells via ST2L under

13、GlucL conditions.IL-33 stimulated signalling pathways that promote cell deathWe found that incubating P29 cells in GlucL or Glnmedium quickly resulted in the phosphorylation of p38 MAPK and JNK but not of p44/42 MAPK, IB- or Akt The addition of rIL-33 enhanced the phosphorylation of p38 MAPK and JNK

14、, and IB- in P29 cells.Interestingly, rIL-33 quickly inhibited AMP-activated proteinkinase- (AMPK) phosphorylation and enhanced mammalian target of rapamycin (mTOR) S2448 phosphorylation at later time points In both cases, SB203580 and rapamycin attenuated the death-enhancing effect of rIL-33mTOR ph

15、osphorylation was inhibited by the mTOR inhibitor rapamycin but not by the p38 MAPK inhibitor SB203580not affect p38 MAPK phosphorylation in A11 cellsThese results indicate that the activation of both p38 MAPK and mTOR is essential for inducing P29 cell deathIL-33 primarily induced programmed oncosi

16、s in P29 cells under nutrient-depleted conditionsNotably,the increase in the number of cells with cytoplasmic blisters and karyolysis, which are unique morphological features of oncosis, was remarkable in rIL-33-treated P29 cells but not in A11 cells under GlucL and Gln conditionsThese results indic

17、ate that intact mitochondrial function is required for eliciting the cell deathenhancing activity of IL-33 in P29 cells. Collectively, on the basis of the facts that triggering ST2Lfollowed by activating p38 MAPK and mTOR and intactmitochondria are required for IL-33-enhanced cell death,which is cha

18、racterised by cellular blisters and karyolysis, weconclude that IL-33 enhances the programmed oncosis37 ofP29 cells under nutrient-depleted conditions.IL-1 enhances the death of P29 cells under nutrientdepleted conditions partly through IL-33 induction.P29 cells proliferated rapidly in IL-33/ mice.IL-33 facilitates high-metastatic cell selection under in vitro conditions mimicking the tumour microenvironment.D