Calreticulin promotes EMT in pancreatic cancer via mediating Ca2+ dependent acute and chronic endoplasmic reticulum stress
Background: Our previous study showed that calreticulin (CRT) promoted EGF-induced epithelial-mesenchymal transition (EMT) in pancreatic cancer (PC) via Integrin/EGFR-ERK/MAPK signaling. We next investigated the novel signal pathway and molecular mechanism involving the oncogenic role of CRT in PC.
Methods: We investigated the potential role and mechanism of CRT in regulating intracellular free Ca2+ dependent acute and chronic endoplasmic reticulum stress (ERS)-induced EMT in PC in vitro and vivo.
Results: Thapsigargin (TG) induced acute ERS via increasing intracellular free Ca2+ in PC cells, which was reversed by CRT silencing. Additionally, CRT silencing inhibited TG-induced EMT in vitro by reversing TG-induced changes of the key proteins in EMT signaling (ZO-1, E-cadherin and Slug) and ERK/MAPK signaling (pERK). TG-promoted cell invasion and migration was also rescued by CRT silencing but enhanced by IRE1α silencing (one of the key stressors in unfolded protein response). Meanwhile, CRT was co-immunoprecipitated and co-localized with IRE1α in vitro and its silencing led to the chronic ERS via upregulating IRE1α independent of IRE1-XBP1 axis. Moreover, CRT silencing inhibited IRE1α silencing-promoted EMT, including inhibiting the activation of EMT and ERK/MAPK signaling and the promotion of cell mobility. In vivo, CRT silencing decreased subcutaneous tumor size and distant liver metastasis following with the increase of IRE1α expression. A negative relationship between CRT and IRE1α was also observed in clinical PC samples, which coordinately promoted the advanced clinical stages and poor prognosis of PC patients.
Conclusions: CRT promotes EMT in PC via mediating intracellular free Ca2+ dependent TG-induced acute ERS and IRE1α-mediated chronic ERS via Slug and ERK/MAPK signaling.
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This is a list of supplementary files associated with this preprint. Click to download.
Supplemental Figure 1. The statistic data of WB in Figure 1. A The quantified data of WB in Figure 2A. B The quantified data of WB in Figure 2B. C The quantified data of WB in Figure 2C. D The quantified data of WB in Figure 2D.
Supplemental Figure 2. IRE1α silencing enhanced TG-induced the increase of cell migration and invasion in vitro. A, B Cell invasion in Control, IRE1αsiRNA, TG and IRE1αsiRNA combing TG groups of Capan-2 (A) and SW1990 cells (B). C, D Cell migration in Control, IRE1αsiRNA, TG and IRE1αsiRNA combing TG groups of Capan-2 (C) and SW1990 cells (D). Data are shown as mean ± SD. *P < 0.05, **P < 0.01 versus control.
Supplemental Figure 3. The statistic data of WB in Figure 5. A The quantified data of WB in Figure 5A. B The quantified data of WB in Figure 5B. C The quantified data of WB in Figure 5C. D The quantified data of WB in Figure 5D.
Posted 04 Sep, 2020
On 07 Oct, 2020
On 06 Sep, 2020
On 04 Sep, 2020
Received 04 Sep, 2020
On 31 Aug, 2020
Invitations sent on 31 Aug, 2020
On 30 Aug, 2020
On 30 Aug, 2020
On 05 Jul, 2020
Received 04 Jul, 2020
Received 04 Jul, 2020
On 28 Jun, 2020
On 23 Jun, 2020
On 22 Jun, 2020
Invitations sent on 22 Jun, 2020
On 21 Jun, 2020
On 21 Jun, 2020
On 21 Jun, 2020
Calreticulin promotes EMT in pancreatic cancer via mediating Ca2+ dependent acute and chronic endoplasmic reticulum stress
Posted 04 Sep, 2020
On 07 Oct, 2020
On 06 Sep, 2020
On 04 Sep, 2020
Received 04 Sep, 2020
On 31 Aug, 2020
Invitations sent on 31 Aug, 2020
On 30 Aug, 2020
On 30 Aug, 2020
On 05 Jul, 2020
Received 04 Jul, 2020
Received 04 Jul, 2020
On 28 Jun, 2020
On 23 Jun, 2020
On 22 Jun, 2020
Invitations sent on 22 Jun, 2020
On 21 Jun, 2020
On 21 Jun, 2020
On 21 Jun, 2020
Background: Our previous study showed that calreticulin (CRT) promoted EGF-induced epithelial-mesenchymal transition (EMT) in pancreatic cancer (PC) via Integrin/EGFR-ERK/MAPK signaling. We next investigated the novel signal pathway and molecular mechanism involving the oncogenic role of CRT in PC.
Methods: We investigated the potential role and mechanism of CRT in regulating intracellular free Ca2+ dependent acute and chronic endoplasmic reticulum stress (ERS)-induced EMT in PC in vitro and vivo.
Results: Thapsigargin (TG) induced acute ERS via increasing intracellular free Ca2+ in PC cells, which was reversed by CRT silencing. Additionally, CRT silencing inhibited TG-induced EMT in vitro by reversing TG-induced changes of the key proteins in EMT signaling (ZO-1, E-cadherin and Slug) and ERK/MAPK signaling (pERK). TG-promoted cell invasion and migration was also rescued by CRT silencing but enhanced by IRE1α silencing (one of the key stressors in unfolded protein response). Meanwhile, CRT was co-immunoprecipitated and co-localized with IRE1α in vitro and its silencing led to the chronic ERS via upregulating IRE1α independent of IRE1-XBP1 axis. Moreover, CRT silencing inhibited IRE1α silencing-promoted EMT, including inhibiting the activation of EMT and ERK/MAPK signaling and the promotion of cell mobility. In vivo, CRT silencing decreased subcutaneous tumor size and distant liver metastasis following with the increase of IRE1α expression. A negative relationship between CRT and IRE1α was also observed in clinical PC samples, which coordinately promoted the advanced clinical stages and poor prognosis of PC patients.
Conclusions: CRT promotes EMT in PC via mediating intracellular free Ca2+ dependent TG-induced acute ERS and IRE1α-mediated chronic ERS via Slug and ERK/MAPK signaling.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
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Figure 8
Figure 9