Overcoming resistance is one of the most challenging features in current anticancer therapy. Autophagy is a cellular process that confers resistance in some advanced tumors, since it enables cancer cells to adapt to stressful situations, such as anticancer treatments. Hence, the inhibition of this cytoprotective autophagy leads to tumor cells sensitization and death. In this regard, we designed a novel potent anionophore compound that specifically targets lysosomes, called LAI-1 (late-stage autophagy inhibitor-1), and evaluated its role in blocking autophagy and its potential anticancer effects in three lung cancer cell lines from different histological subtypes. Compared to other autophagy inhibitors, such as chloroquine and 3-Methyladenine, the LAI-1 treatment induced more potent anticancer effects in all tested cancer cells. LAI-1 was able to efficiently target and deacidify lysosomes, while acidifying cytoplasmic pH. Consequently, LAI-1 efficiently blocked autophagy, indicated by the increased LC3-II/I ratio and p62/SQSTM1 levels. Moreover, no colocalization was observed between autophagosomes, marked with LC3 or p62/SQSTM1, and lysosomes, stained with LAMP-1, after the LAI-1 treatment, indicating the blockage of autophagolysosome formation. Furthermore, LAI-1 induced cell death by activating apoptosis (enhancing the cleavage of caspase-3 and PARP) or necrosis, depending on the cancer cell line. Finally, LAI-1 sensitized cancer cells to the first-line chemotherapeutic agent cisplatin. Altogether, LAI-1 is a new late-stage autophagy inhibitor that causes lysosomal dysfunction and the blockage of autophagolysosome formation, as well as potently induces cancer cell death and sensitization to conventional treatments at lower concentrations than other known autophagy inhibitors, appearing as a potential new therapeutic approach to overcome cancer resistance.

Therapy resistance in human cancers is a major limitation in Clinical Oncology. In this regard, overexpression of anti-apoptotic proteins, such as survivin, has been described in several tumors, contributing to this clinical issue. Survivin has a dual role in key cellular functions, inducing cell cycle progression and inhibiting apoptosis; thus, survivin is an attractive target for cancer therapy. Therefore, we focused on identifying and validating a novel specific, directly binding survivin inhibitor for cancer treatment and tumor sensitization to conventional proapoptotic therapies. In this work, we conducted a structure-based high-throughput virtual screening at the survivin homodimerization domain. Asenapine Maleate (AM), an approved drug for central nervous system diseases, was identified as a direct binder of the survivin homodimerization domain and it significantly affected cell viability of lung, colon, and brain cancer cell lines. Direct interaction of AM to survivin protein was corroborated by surface plasmon resonance and a specific survivin protein decrease was observed in cancer cells, compared to other inhibitors of apoptosis proteins. Therapeutic in vivo studies showed an impairment of tumor growth in AM-treated mice. Finally, a synergistic anticancer effect was detected in vitro when combined with different conventional chemotherapies, and in vivo studies showed higher antitumor effects when combined with cisplatin. Altogether, our results identify AM as a specific direct binding inhibitor of survivin, showing anticancer properties in vitro and in vivo and sensitizing effects when combined with cisplatin, opening the possibility of repositioning this approved drug for cancer treatment.