lys01 and Glioblastoma

Glioblastoma (GBM) is one of the most malignant primary brain tumors and its prognosis is very poor. Lysosome-dependent cell death is mainly caused by lysosomal membrane permeabilization (LMP), a process in which the lysosome loses its membrane integrity and lysosomal contents are released into the cytosol. Lysosomotropic agent, a kind of compound that selectively accumulates in the lysosomes, is one of the most important inducers of LMP. As a newly-synthetic lysosomotropic agent, Lys05 showed efficient autophagy inhibiting and antitumor effect. But its mechanisms are not well illustrated. Here, we studied whether Lys05 has antiglioma activity. We found that Lys05 decreased cell viability and reduced cell growth of glioma U251 and LN229 cells. After Lys05 treatment, autophagic flux is inhibited and lysosome function is impaired. We also found that Lys05 caused LMP and mitochondrial depolarization. Finally, Lys05 increased radiosensitivity in an LMP-dependent manner. For the first time, our findings indicate that LMP contributes to radiosensitivity in GBM cells. Therefore, LMP inducer, Lys05 might be a promising compound in the treatment of GBM cells.

Topics: Aminoquinolines; Apoptosis; Autophagy; Cell Membrane Permeability; Cell Proliferation; Gamma Rays; Glioblastoma; Humans; Lysosomes; Polyamines; Radiation Tolerance; Radiation-Sensitizing Agents; Tumor Cells, Cultured

Autophagy is a lysosome-dependent degradative process that protects cancer cells from multiple stresses. In preclinical models, autophagy inhibition with chloroquine (CQ) derivatives augments the efficacy of many anticancer therapies, but CQ has limited activity as a single agent. Clinical trials are underway combining anticancer agents with hydroxychloroquine (HCQ), but concentrations of HCQ required to inhibit autophagy are not consistently achievable in the clinic. We report the synthesis and characterization of bisaminoquinoline autophagy inhibitors that potently inhibit autophagy and impair tumor growth in vivo. The structural motifs that are necessary for improved autophagy inhibition compared with CQ include the presence of two aminoquinoline rings and a triamine linker and C-7 chlorine. The lead compound, Lys01, is a 10-fold more potent autophagy inhibitor than HCQ. Compared with HCQ, Lys05, a water-soluble salt of Lys01, more potently accumulates within and deacidifies the lysosome, resulting in impaired autophagy and tumor growth. At the highest dose administered, some mice develop Paneth cell dysfunction that resembles the intestinal phenotype of mice and humans with genetic defects in the autophagy gene ATG16L1, providing in vivo evidence that Lys05 targets autophagy. Unlike HCQ, significant single-agent antitumor activity is observed without toxicity in mice treated with lower doses of Lys05, establishing the therapeutic potential of this compound in cancer.

Topics: Adenocarcinoma; Aminoquinolines; Animals; Antimalarials; Antineoplastic Agents; Autophagy; Autophagy-Related Proteins; Brain Neoplasms; Carrier Proteins; Cell Death; Colonic Neoplasms; Drug Resistance, Neoplasm; Glioblastoma; HT29 Cells; Humans; Hydroxychloroquine; Intestinal Obstruction; Lysosomes; Mice; Mice, Nude; Polyamines; Xenograft Model Antitumor Assays