LCDR maintains the integrity of lysosomal membrane by hnRNP K-stabilized LAPTM5 transcript and promotes cell survival

Lysosome plays important roles in cellular homeostasis and its dysregulation is associated with cancer. However, the regulation and underlying mechanism of lysosome in cancer survival remain incompletely understood. Here, we reveal a role for a histone acetylation-regulated long non-coding RNA termed as lysosome cell death regulator (LCDR) in lung cancer cell survival, knockdown of which promotes apoptosis. Mechanistically, LCDR binds to heterogenous nuclear ribonucleoprotein K (hnRNP K) to regulate the stability of lysosomal-associated protein transmembrane 5 (LAPTM5) transcript that maintain integrity of lysosomal membrane. Consequently, knockdown of LCDR, hnRNP K or LAPTM5 promotes lysosomal membrane permeabilization and lysosomal cell death-mediated apoptosis. LAPTM5 overexpression or cathepsin B inhibitor partially restores the effects of this axis on lysosomal cell death. Clinically, LCDR/hnRNP K/LAPTM5 are upregulated in lung cancer tissues and coexpression of this axis shows the increased diagnostic value for lung cancer. These findings shed light on LCDR/hnRNP K/LAPTM5 as potential therapeutic targets and targeting lysosome is a promising strategy in cancer treatment. Overall design: We conducted total RNA sequencing after the BEAS-2B and NCI-H1299 were treated with DMSO and TSA for 24 hours, LCDR and hnRNPK genes were knocked down in NCI-H1299 cell lines. Totally 22 samples were generated.