The HIF target MAFF promotes tumor invasion and metastasis through IL11 and STAT3 signaling

Hypoxia plays a critical role in tumor progression including invasion and metastasis. To determine critical genes regulated by hypoxia that promote invasion and metastasis, we screen fifty hypoxia inducible genes for their effects on invasion. In this study, we identify v-maf musculoaponeurotic fibrosarcoma oncogene homolog F (MAFF) as a potent regulator of tumor invasion without affecting cell viability. MAFF expression is elevated in metastatic breast cancer patients and is specifically correlated with hypoxic tumors. Combined ChIP- and RNA-sequencing identifies IL11 as a direct transcriptional target of the heterodimer between MAFF and BACH1, which leads to activation of STAT3 signaling. Inhibition of IL11 results in similar levels of metastatic suppression as inhibition of MAFF. This study demonstrates the oncogenic role of MAFF as an activator of the IL11/STAT3 pathways in breast cancer.


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Amato Giaccia
March/03/2021 Leica Application Suite X (LAS X) was used to take images using Leica DMi8. Image Lab 4.0 was used to collect western blot images from Chemidoc.
ImageJ was used to perform image analysis for invasion assay, H&E staining, and IHC. Graphpad prism 8 was used to generate graph and to perform statistical test.
Raw and processed data for RNA and ChIP-sequencing data (Fig. 5, Supplementary Fig. 5)  For in vitro studies, n=3 or 4 were chosen to test statistical significance, while n=5-10 were used for in vivo studies. The number of replicates were determined based on minimum number of replicate to achieve statistical power.
No data were excluded.
All attempts to replicate results were successful. esiRNA screening for cell invasion and survival was performed three times. Real time qPCR, ChIP, luciferase reporter assays were performed three times with 3 technical replicates. For in vitro invasion assay and in vivo IHC, images were taken three representative fields and averaged quantitation was used in each data point. Rest of experiments were performed with three biological replicates.
Randomization was not required, since we did not compare any treatment groups requiring randomization to form groups.
Quantification of in vitro invasion assay and in vivo H&E and IHC images were performed in blind ways. Rest of experiments did not require blinding for analysis.