KL and neoplasm: In addition, pH-responsive liposomes modified with KLA peptides allowed for mitochondrial-oriented delivery of PTX, the positively charged KLA peptide could target mitochondria and promote cellular uptake, which further improved the chemotherapeutic efficacy against A549 cells and PTX-resistant A549 cells both in vitro and in vivo, with a tumor growth inhibition of 86.7% [87].