Tumor lineage plasticity is emerging as a critical mechanism of therapeutic resistance and tumor relapse. Highly plastic tumor cells can undergo phenotypic switching to a drug-tolerant state to avoid drug toxicity. Here, we investigate the transmembrane tight junction protein Claudin6 (CLDN6) as a therapeutic target related to lineage plasticity for hepatocellular carcinoma (HCC). CLDN6 was highly expressed in embryonic stem cells but markedly decreased in normal tissues. Reactivation of CLDN6 was frequently observed in HCC tumor tissues as well as in premalignant lesions. Functional assays indicated that CLDN6 is not only a tumor-associated antigen but also conferred strong oncogenic effects in HCC. Overexpression of CLDN6 induced phenotypic shift of HCC cells from hepatic lineage to biliary lineage, which was more refractory to sorafenib treatment. The enhanced tumor lineage plasticity and cellular identity change were potentially induced by the CLDN6/TJP2 (tight junction protein 2)/YAP1 (Yes-associated protein 1) interacting axis and further activation of the Hippo signaling pathway. A de novo anti-CLDN6 monoclonal antibody conjugated with cytotoxic agent (Mertansine) DM1 (CLDN6-DM1) was developed. Preclinical data on both HCC cell lines and primary tumors showed the potent antitumor efficiency of CLDN6-DM1 as a single agent or in combination with sorafenib in HCC treatment.

Cancer stem cells (CSCs) are responsible for the melanoma recurrence, progression, and ineffective therapy. Despite striking anti-CSCs results in immunotherapy with anti-programmed death-1 antibodies (aPD-1), the therapeutic efficacy is restricted by the evolution of immune evasion of CSCs. Here, a wearable silk-based microneedle device (SMND) integrating a synergistic immunity and hydrogen therapy is developed. The device mainly consists of a double-layered MN patch (DLMNP), which employs aPD-1 loaded silk fibroin (SF) as the inner matrix for immunotherapy, while ammonia borane-loaded mesoporous silica nanoparticles (AB-MSN) encapsulated polycaprolactone as the outer thermal-responsive coating for H 2 releasing. SMND can realize thermally responsive drug release triggered by a smartphone for a sustained anti-CSCs therapy. In B16F10-CSCs bearing mice melanoma models, the results demonstrates that the synergistic treatment strategy can realize a satisfying antitumor and anti-CSCs efficacy, which is accompanied by a minimized systemic toxicity. In summary, the smart and synergistic anti-CSCs features endow SMND as a highly functional platform, which can be potentially extended to chronic disease therapy.

Tracking biological fate of exosomes in vivo is essential for evaluating their functions, delivery efficacy, biosafety, and is invaluable for guiding exosome-based therapy.