Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2017 Mar 28;8(13):20741-20750.
doi: 10.18632/oncotarget.15119.

IL-6 secreted by cancer-associated fibroblasts promotes epithelial-mesenchymal transition and metastasis of gastric cancer via JAK2/STAT3 signaling pathway

Xiongyan Wu  1 , Pan Tao  1 , Quan Zhou  1 , Jie Li  1 , Zhenjia Yu  1 , Xiaofeng Wang  1 , Jiaanfang Li  1 , Chen Li  1 , Min Yan  1 , Zhenggang Zhu  1 , Bingya Liu  1 , Liping Su  1
Affiliations

IL-6 secreted by cancer-associated fibroblasts promotes epithelial-mesenchymal transition and metastasis of gastric cancer via JAK2/STAT3 signaling pathway

Xiongyan Wu et al. Oncotarget. .

Abstract

Cancer-associated fibroblasts (CAFs), as the activated fibroblasts in tumor stroma, are important modifiers of tumor progression. However, the molecular mechanisms underlying the tumor-promoting properties of CAFs in gastric cancer remain unclear. Here, we show that CAFs isolated from gastric cancer produce significant amounts of interleukin-6 (IL-6). CAFs enhances the migration and EMT of gastric cancer cells through the secretion of IL-6 that activates Janus kinase 2/signal transducers and activators of transcription (JAK2/STAT3) pathway in gastric cancer cells, while deprivation of IL-6 using a neutralizing antibody or inhibition of JAK/STAT3 pathway with specific inhibitor AG490 markedly attenuates these phenotypes in gastric cancer cells induced by CAFs. Moreover, silencing IL-6 expression in CAFs or inhibiting JAK2/STAT3 pathway in gastric cancer cells impairs tumor peritoneal metastasis induced by CAFs in vivo. Taken together, these results suggest that CAFs in the tumor microenvironment promote the progression of gastric cancer through IL-6/JAK2/STAT3 signaling, and IL-6 targeted therapy could be a complementary approach against gastric cancer by exerting their action on stromal fibroblasts.

Keywords: JAK/STAT3; cancer-associated fibroblasts; gastric cancer; interleukin-6.

PubMed Disclaimer

Conflict of interest statement

CONFLICTS OF INTEREST

The authors made no disclosures.

Figures

Figure 1
Figure 1. IL-6 is highly expressed in gastric CAFs
(A, B) The expression of IL-6 in both serum and cancer tissues in gastric cancer patient was detected by ELISA. (C) Frozen tissue sections from gastric cancer and adjacent non-tumor tissue were immunostained by DAPI (nucleus), FITC (IL-6) and PE (α-SMA) (200×). (D) IL-6 protein expression level in the gastric cancer cells (SNU-1, MKN45, SGC7901 and MKN28), gastric CAFs and normal fibroblasts (NFs) was quantified 24hrs after change the culture medium by ELISA. *P < 0.05.
Figure 2
Figure 2. CAFs enhance the migration of gastric cancer cells via the secretion of IL-6
(A) The effect of CAFs on cell migration was determined 24 hrs after in the presence of IL-6 neutralizing antibody or IgG isotype control antibody. Representative photographs of migratory cells on the membrane (magnification, 100×) are shown. (B, C) Migratory Cells were counted in ten randomly selected microscopic fields. Values are represented as mean ± SD of three independent experiments. *P < 0.05.
Figure 3
Figure 3. CAFs promote EMT of gastric cancer cells via the secretion of IL-6
(A) Protein expression of E-cadherin, N-cadherin and ZEB2 in gastric cancer cells SGC-7901 and MKN28 co-cultured with CAFs in the presence of IL-6 neutralizing antibody or IgG isotype control antibody was analyzed by western blot. Representative images from one of the three independent experiments are presented. (B) Densitometric analysis of E-cadherin, N-cadherin and ZEB2 expression is shown.
Figure 4
Figure 4. CAFs-derived IL-6 enhances the migration and EMT of gastric cancer cells via the activation of JAK2/STAT3 pathway
(A, B) Protein levels of p-STAT3, STAT3, p-JAK2 and JAK2 in both SGC-7901 and MKN28 co-cultured with CAFs in the presence of IL-6 neutralizing antibody or AG490 were analyzed by western blot. Representative results from one of the three independent experiments are presented. (C, D) Densitometric analysis of p-STAT3, STAT3, p-JAK2 and JAK2 expression is shown. (E) The effect of CAFs on cell migration was assayed in the presence of AG490. Migratory Cells were counted in ten randomly selected microscopic fields. Values are represented as mean ± SD of three independent experiments. *P < 0.05. (F) Protein expression of E-cadherin, N-cadherin and ZEB2 in gastric cancer cells SGC-7901 and MKN28 co-cultured with CAFs in the presence of AG490 or equivalent concentration of DMSO was analyzed by western blot. Representative images from one of the three independent experiments are presented. (G) Densitometric analysis of E-cadherin, N-cadherin and ZEB2 expression is shown.
Figure 5
Figure 5. Blocking IL-6-JAK2-STAT3 pathway impairs tumor peritoneal dissemination and metastasis induced by CAFs in vivo
(A) IL-6 mRNA levels in CAFs treated with siRNA or siNC were detected by qRT-PCR. (B) IL-6 protein concentration in the medium conditioned by CAFs treated with (siIL-6) or control siRNA (siNC) were measured by ELISA. (C) SGC-7901 cells and SGC-7901 cells mixed with CAFs that were transfected with IL-6 siRNA (siIL-6) or control siRNA (siNC) were inoculated into nude mice. Mice co-injected with SGC-7901 cells and CAFs were administered i. p with AG490 (500 μg/100 ul/mouse) or equivalent concentration of DMSO once a week. The peritoneal nodules (red arrows) were observed after 30 days (N = 5 per group). (D) Average peritoneal nodules from nude mice are shown. Data are representative of three independent experiments. *P < 0.05.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Torre LA, Bray F, Siegel RL, Ferlay J, Lortet-Tieulent J, Jemal A. Global cancer statistics, 2012. CA Cancer J Clin. 2015;65:87–108. - PubMed
    1. Moon YW, Jeung HC, Rha SY, Yoo NC, Roh JK, Noh SH, Kim BS, Chung HC. Changing patterns of prognosticators during 15-year follow-up of advanced gastric cancer after radical gastrectomy and adjuvant chemotherapy: a 15-year follow-up study at a single korean institute. Annals of surgical oncology. 2007;14:2730–2737. - PubMed
    1. Thiery JP. Epithelial-mesenchymal transitions in tumour progression. Nature reviews Cancer. 2002;2:442–454. - PubMed
    1. Yang J, Weinberg RA. Epithelial-mesenchymal transition: at the crossroads of development and tumor metastasis. Developmental cell. 2008;14:818–829. - PubMed
    1. Zeisberg M, Neilson EG. Biomarkers for epithelial-mesenchymal transitions. J Clin Invest. 2009;119:1429–1437. - PMC - PubMed

MeSH terms