Erlotinib-guided self-assembled trifunctional click nanotheranostics for distinguishing druggable mutations and synergistic therapy of NSCLC.

The outcome of molecular targeted therapies is restricted by the ambiguous molecular subtypes of nonsmall cell lung cancer (NSCLC), which are difficult to be defined with druggable mutations, and the inevitable emergence of drug-resistance. Here we used the Cu-catalyzed click chemistry to synthesize a chitosan-based self-assembled nanotheranostics (CE7Ns) composed of a near-infrared (NIR) fluorescent photosensitizer Cy7 and molecular targeted drug erlotinib. The well-characterized CE7Ns can release erlotinib and Cy7 fast under acidic condition in the presence of lysozyme, distinguish three molecular subtypes of NSCLC, and specifically bind to the erlotinib-sensitive epidermal growth factor receptor (EGFR)-mutated PC-9 cells. The uptake of CE7Ns is much more in PC-9 cells than in other NSCLC cells, thus generating a notable fluorescence signal in PC-9 cells. Upon NIR irradiation, Cy7 in CE7Ns produces high reactive oxygen species in PC-9 cells. The synergistic effect between erlotinib-targeted therapy and photodynamic therapy significantly up-regulates cancer suppressor p53 and inhibits Survivin, which results in more apoptosis and cell cycle arrest. Upon intravenous administration, the erlotinib-guided CE7Ns significantly accumulate in PC-9-seeded mouse lungs and produce strong fluorescence. Upon NIR irradiation, CE7Ns significantly inhibit the subcutaneously implanted PC-9 tumor growth. This study provides, for the first time, a novel strategy to synthesize a multifunctional theranostic entity to simultaneously distinguish and image druggable mutations and combine targeted therapy with photodynamic therapy to overcome drug resistance.