Observational evidence is mounting nowadays for AGN acting on the ISM (molecular and atomic) of its host galaxy on large scales, including the regions of star formation, and, through this, affecting the evolution and the transformation of the host galaxy. AGN-driven massive outflows have been seen in the molecular gas component in several local QSOs/ULIRGs, and they start to be found in a few high redshift QSOs. These observational results show that massive outflows can invest the bulk of the gas in galaxies on scales of kiloparsecs, supporting models of AGN and galaxy co-evolution through AGN-feedback. Massive molecular outflows are therefore regarded as the long sought mechanism leading to the formation of red passive galaxies, deprived of gas. In this framework, I will present recent results about the massive outflows found in Mrk231 and in NGC6240, two nearby ULIRGs and mergers, hosting powerful AGN. I will show how the tracers of massive outflows, the signatures of AGN feedback, are seen across the spectrum, from the radio to the X-ray domain.