Interleukin-1 alpha mediates the growth proliferative effects of transforming growth factor-beta in p21 null MCF-10A human mammary epithelial cells

Abstract

Transforming growth factor-b type 1 (TGF-b) has been implicated as both a tumor suppressor and a tumor promoter in many solid epithelial cancers. We have previously demonstrated that the cyclin dependent kinase (CDK) inhibitor p21 acts as a molecular switch in determining a growth inhibitory versus growth proliferative response to TGF-b in the spontaneously immortalized human mammary epithelial cell line MCF-10A. We now demonstrate that this proliferative effect of TGF-b is mediated through the proinflammatory cytokine, interleukin-1a (IL-1a). Using gene expression array analysis, we identified IL-1a as a cytokine specifically upregulated only in cells lacking p21 and only upon TGF-b stimulation. Cell proliferation assays verified that recombinant IL-1a was capable of inducing a growth proliferative response in p21 null MCF-10A cells, while neutralizing antibodies against IL-1a prevented the growth proliferative effects of TGF-b. Mechanistically, both the CDK and proliferating cell nuclear antigen (PCNA) inhibitory functions of p21 were responsible for preventing TGF-b induced cell proliferation, but only PCNA inhibition by p21 regulated IL-1a gene expression. These studies demonstrate a novel role for IL-1a in mediating a proliferative response to TGF-b signaling, and suggest that therapies directed against IL-1a could abate the growth proliferative effects of TGF-b without compromising its tumor suppressive function.

Tamoxifen-stimulated growth of breast cancer due to p21 loss

“…Importantly, this cDNA retains other functional properties of p21 (31), and transfection efficiencies were equivalent among wild-type p21, p21 cdkϪ, and empty vector controls as demonstrated by our group (SI Fig. 8A) and by others (30). In contrast to wild-type p21, the vector control and mutant p21 cdkϪ constructs had no effect on tamoxifen resistance ( Fig.…”

“…Nevertheless, by cell count analysis, there was Ϸ2-fold less growth, which was highly statistically significant (SI Table 2, P Ͻ 0.0001). We next mutated DNA sequences encoding three amino acids in the CDK-binding domain of the p21 cDNA (p21 cdkϪ) and transfected this construct into ERIK cells as described (30). Importantly, this cDNA retains other functional properties of p21 (31), and transfection efficiencies were equivalent among wild-type p21, p21 cdkϪ, and empty vector controls as demonstrated by our group (SI Fig.…”

“…Transient transfections and growth assays were preformed as described (15,16,30). Briefly, empty vector, wild-type p21 cDNA, and a mutant p21 cDNA devoid only of CDK inhibitory function were transiently transfected into ERIK cells with FUGENE6 (Roche Diagnostics) following the manufacturer's recommendations and then grown under EGF-free conditions with and without 10 nM 17-␤-estradiol or 1 M 4-OH-tamoxifen as described above.…”

Heat Shock Protein Hsp72 Controls Oncogene-Induced Senescence Pathways in Cancer Cells

“…MCF10A p21 Ϫ/Ϫ cells were kindly provided by B. Park (27). MCF10A cells were cultivated in Dulbecco's modified Eagle's medium-F12 medium supplemented with 5% horse serum, hydrocortisone (500 ng/ml), insulin (10 g/ml), cholera toxin (100 ng/ml), and epidermal growth factor ([20 ng/ml]).…”

The miR-424(322)/503 cluster orchestrates remodeling of the epithelium in the involuting mammary gland

“…The mammary cell line MCF-10A is a widely used model to study TGF-b response in mammary epithelial cells (Iavarone and Massague 1997;Karakas et al 2006). Despite being null for the INK4B gene, these cells retain the ability to arrest after being exposed to TGF-b.…”