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IL-1 β induces IL-6 production and increases invasiveness and estrogen-independent growth in a TG2-dependent manner in human breast cancer cells

View Article: PubMed Central - PubMed

ABSTRACT

Background: We previously reported that IL-6 and transglutaminase 2 (TG2) were expressed in more aggressive basal-like breast cancer cells, and TG2 and IL-6 expression gave these cells stem-cell-like phenotypes, increased invasive ability, and increased metastatic potential. In the present study, the underlying mechanism by which IL-6 production is induced in luminal-type breast cancer cells was evaluated, and TG2 overexpression, IL-1β stimulation, and IL-6 expression were found to give cancerous cells a hormone-independent phenotype.

Methods: Luminal-type breast cancer cells (MCF7 cells) were stably transfected with TG2. To evaluate the requirement for IL-6 neogenesis, MCF7 cells were stimulated with various cytokines. To evaluate tumorigenesis, cancer cells were grown in a three-dimensional culture system and grafted into the mammary fat pads of NOD/scid/IL-2Rγ−/− mice.

Results: IL-1β induced IL-6 production in TG2-expressing MCF7 cells through an NF-kB-, PI3K-, and JNK-dependent mechanism. IL-1β increased stem-cell-like phenotypes, invasiveness, survival in a three-dimensional culture model, and estrogen-independent tumor growth of TG2-expressing MCF7 cells, which was attenuated by either anti-IL-6 or anti-IL-1β antibody treatment.

Conclusion: Within the inflammatory tumor microenvironment, IL-1β increases luminal-type breast cancer cell aggressiveness by stimulating IL-6 production through a TG2-dependent mechanism.

Electronic supplementary material: The online version of this article (doi:10.1186/s12885-016-2746-7) contains supplementary material, which is available to authorized users.

No MeSH data available.


Related in: MedlinePlus

TG2 overexpression of breast cancer cells revealed EMT and stem-cell-like phenotypes. MCF7 luminal-type breast cancer cells were stably transfected with TG2 (TG2) and control vector (Cont) and EMT and stem-cell markers were compared using Western blot (a), RT-PCR (b), and flow cytometry (c). a-c All data shown are representative of three independent experiments
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Fig1: TG2 overexpression of breast cancer cells revealed EMT and stem-cell-like phenotypes. MCF7 luminal-type breast cancer cells were stably transfected with TG2 (TG2) and control vector (Cont) and EMT and stem-cell markers were compared using Western blot (a), RT-PCR (b), and flow cytometry (c). a-c All data shown are representative of three independent experiments

Mentions: To define the signaling pathways involved in TG2-dependent IL-6 expression in breast cancer cells further, TG2 was overexpressed in otherwise TG2- and IL-6-negative luminal-type breast cancer cells (MCF7). The whole sequence of human TG2 was successfully overexpressed (Fig. 1a). Since increased aggressiveness conferred by TG2 expression in breast cancer cells correlates with EMT and stem-cell-like phenotypes, these characteristics were evaluated in TG2 overexpressing cells. Expression of E-cadherin and cell-to-cell junction formation were decreased in TG2-overexpressing MCF7 cells (MCF7_TG2) compared to the control MCF-7 cells (MCF7_Cont) (Fig. 1a and Additional file 1: Figure S1). Snail2, an EMT inducer, and tissue inhibitor of metalloproteinase (TIMP) 1, 2, and 3 were increased in MCF7_TG2 cells compared to the control cells (Fig. 1b). CD44, a breast cancer stem cell surface phenotype marker, was increased in MCF7_TG2 cells compared to control cells (Fig. 1c).Fig. 1


IL-1 β induces IL-6 production and increases invasiveness and estrogen-independent growth in a TG2-dependent manner in human breast cancer cells
TG2 overexpression of breast cancer cells revealed EMT and stem-cell-like phenotypes. MCF7 luminal-type breast cancer cells were stably transfected with TG2 (TG2) and control vector (Cont) and EMT and stem-cell markers were compared using Western blot (a), RT-PCR (b), and flow cytometry (c). a-c All data shown are representative of three independent experiments
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5017052&req=5

Fig1: TG2 overexpression of breast cancer cells revealed EMT and stem-cell-like phenotypes. MCF7 luminal-type breast cancer cells were stably transfected with TG2 (TG2) and control vector (Cont) and EMT and stem-cell markers were compared using Western blot (a), RT-PCR (b), and flow cytometry (c). a-c All data shown are representative of three independent experiments
Mentions: To define the signaling pathways involved in TG2-dependent IL-6 expression in breast cancer cells further, TG2 was overexpressed in otherwise TG2- and IL-6-negative luminal-type breast cancer cells (MCF7). The whole sequence of human TG2 was successfully overexpressed (Fig. 1a). Since increased aggressiveness conferred by TG2 expression in breast cancer cells correlates with EMT and stem-cell-like phenotypes, these characteristics were evaluated in TG2 overexpressing cells. Expression of E-cadherin and cell-to-cell junction formation were decreased in TG2-overexpressing MCF7 cells (MCF7_TG2) compared to the control MCF-7 cells (MCF7_Cont) (Fig. 1a and Additional file 1: Figure S1). Snail2, an EMT inducer, and tissue inhibitor of metalloproteinase (TIMP) 1, 2, and 3 were increased in MCF7_TG2 cells compared to the control cells (Fig. 1b). CD44, a breast cancer stem cell surface phenotype marker, was increased in MCF7_TG2 cells compared to control cells (Fig. 1c).Fig. 1

View Article: PubMed Central - PubMed

ABSTRACT

Background: We previously reported that IL-6 and transglutaminase 2 (TG2) were expressed in more aggressive basal-like breast cancer cells, and TG2 and IL-6 expression gave these cells stem-cell-like phenotypes, increased invasive ability, and increased metastatic potential. In the present study, the underlying mechanism by which IL-6 production is induced in luminal-type breast cancer cells was evaluated, and TG2 overexpression, IL-1β stimulation, and IL-6 expression were found to give cancerous cells a hormone-independent phenotype.

Methods: Luminal-type breast cancer cells (MCF7 cells) were stably transfected with TG2. To evaluate the requirement for IL-6 neogenesis, MCF7 cells were stimulated with various cytokines. To evaluate tumorigenesis, cancer cells were grown in a three-dimensional culture system and grafted into the mammary fat pads of NOD/scid/IL-2Rγ−/− mice.

Results: IL-1β induced IL-6 production in TG2-expressing MCF7 cells through an NF-kB-, PI3K-, and JNK-dependent mechanism. IL-1β increased stem-cell-like phenotypes, invasiveness, survival in a three-dimensional culture model, and estrogen-independent tumor growth of TG2-expressing MCF7 cells, which was attenuated by either anti-IL-6 or anti-IL-1β antibody treatment.

Conclusion: Within the inflammatory tumor microenvironment, IL-1β increases luminal-type breast cancer cell aggressiveness by stimulating IL-6 production through a TG2-dependent mechanism.

Electronic supplementary material: The online version of this article (doi:10.1186/s12885-016-2746-7) contains supplementary material, which is available to authorized users.

No MeSH data available.


Related in: MedlinePlus