Early stages of colonization of distant organs by metastatic cancer cells (micrometastasis) remain almost inaccessible to study due to lack of relevant experimental approaches. Here, we show the first 3D tissue engineered model of hepatic micrometastasis of triple negative breast cancer (TNBC). It reproduces characteristic histopathological features of the disease and reveals that metastatic TNBC cells colonize liver parenchymal and stromal extracellular matrix with different speed and by different strategies. These engineered tumors induce the angiogenic switch when grafted in vivo, confirming their metastatic-specific behaviour. Furthermore, we proved feasibility and biological relevance of our model for drug and nanoparticle testing and found a down-regulatory effect of the liver microenvironment of the sensitivity of TNBC cells to chemotherapeutic drug doxorubicin in free and nanoformulated forms. The convenient and affordable methodology established here can be translated to other types of metastatic tumors for basic cancer biology research and adapted for high-throughput assays.