Mazzeo et al. · Nature Communications · 2024
ANKRD1 is a mesenchymal-specific driver of cancer-associated fibroblast activation bridging androgen receptor loss to AP-1 activation
Mazzeo Luigi, Ghosh Soumitra, Di Cicco Emery, Isma Jovan, Tavernari Daniele, Samarkina Anastasia, Ostano Paola, Youssef Markus K., Simon Christian, Dotto G. Paolo
The study
What was asked, and what was found
Mazzeo et al., Nature Communications, 2024 set out to find a switch that turns an ordinary fibroblast into a cancer-associated fibroblast without also driving it into senescence, because senescence is the confound that makes this class of target hard to act on. Comparing transcriptomes of patient-derived cancer-associated fibroblasts against matched normal fibroblasts, of dermal fibroblasts with and without androgen receptor silencing, and of fibroblasts treated with a bromodomain inhibitor, the authors converged on one gene: ANKRD1. It sits directly under androgen receptor repression, rises when that repression is lost, and is raised in fibroblasts from hypertrophic scars, keloids and idiopathic pulmonary fibrosis as well as from tumours. Mechanistically ANKRD1 clamps the AP-1 transcription factor pair, promoting the c-JUN and FOSL2 association and their binding at fibroblast effector genes.
The functional test used antisense oligonucleotides against ANKRD1, purchased from AUM BioTech, alongside a scrambled control. In patient-derived cancer-associated fibroblasts the oligonucleotides brought down ANKRD1 together with the activation genes ACTA2, COL1A1, INHBA and HAS2, and did so without affecting how fast the cells divided. The mechanism moved with the target: the c-JUN and FOSL2 association fell, and c-JUN binding across the regulatory regions of fibroblast effector genes was strongly reduced.
The consequence reached the cancer cells. Fibroblasts pre-treated against ANKRD1 and then co-cultured with squamous carcinoma cells for 7 days supported markedly less cancer cell expansion than controls. In an orthotopic model, carcinoma cells co-injected intradermally with treated fibroblasts formed smaller and less dense tumours than the same cells injected with control fibroblasts on the opposite flank of the same animal. One point matters for how this paper is used: the oligonucleotides here were delivered into the fibroblasts with a transfection reagent at 100 nM, not added to the medium, so this study is evidence about the target and not about unaided uptake.
Key findings
- Knocking down ANKRD1 in patient-derived cancer-associated fibroblasts brought down the fibroblast activation genes with it.(Results, ANKRD1 targeting reproduces the effects of AP1 inhibition on CAF activation)
- The knockdown broke the transcription factor partnership that ANKRD1 holds together, reducing the c-JUN and FOSL2 association and c-JUN binding at fibroblast effector genes.(Results, ANKRD1 targeting reproduces the effects of AP1 inhibition on CAF activation)
- Fibroblasts treated before the experiment lost their ability to help cancer cells expand in co-culture, an effect that lasted 7 days after treatment.(Results, ANKRD1 targeting reproduces the effects of AP1 inhibition on CAF activation)
- The effect carried into animals: tumours grew smaller and less dense when the co-injected fibroblasts had been treated against ANKRD1.(Results, ANKRD1 targeting reproduces the effects of AP1 inhibition on CAF activation)
- ANKRD1 sits directly under androgen receptor control and rises as that control is lost, which is what converts a normal fibroblast into a tumour-supporting one.(Results, ANKRD1 is under direct negative control of AR)
- Targeting ANKRD1 broke the AP-1 complex, reversed the activated fibroblast state, and blocked the tumour-supporting behaviour of those cells in an orthotopic skin cancer model.(Abstract)
For research use only. Not for use in diagnostic or therapeutic procedures.