Fig 2: Cathepsin L regulates lactate dehydrogenase A turnover. A–C, LDHA protein levels were determined by Western blotting from total cell extracts of MEF and HeLa cells. The number of biological replicates per individual experiment is indicated by the number of dots in the bar graphs. Cts Bi and Cts Li stand for Cts B and Cts L inhibitors. D, mRNA expression of LDHA, HIF-1α and c-Myc in MEF cells lacking Cts B, Cts L or WT cells. E,Wild type MEFs were treated with Cts Li for 48 h and mRNA levels of LDHA, HIF-1α and c-Myc were determined by qRT-PCR. At least three biological replicates were used for analysis and data present the mean ± S.E. Statistical significance was determined by one-way ANOVA with Tukey's correction for multiple hypothesis for panels (A–D) and student's t test for panel (E). p values lower than 0.05 were considered significant * p < 0.05, ** p < 0.01.

Fig 3: Two-dimensional (A) and 3D (B) patternsillustrating the proposed binding mode of the co-crystallized ligand GNE-140 in the LDHA binding pocket (PDB code: 4ZVV). Hydrogen bonding interactions with the protein are shown as dashed lines. Green color reflects a hydrophobic area, pink color reflects a high polar area, and blue color reflects a mild polar area.

Fig 4: Two-dimensional (A) and 3D (B) patternsillustrating the proposed binding mode of the compound 4a in the LDHA binding pocket (PDB code: 4ZVV). Hydrogen bonding interactions with the protein are shown as dashed lines. Green color reflects a hydrophobic area, pink color reflects a high polar area, and blue color reflects a mild polar area.

Fig 5: Design of new target derivatives 3–6 via lead modification of known candidates A–C having promising cytotoxic and LDHA inhibitory activities.