PFKL promotes cell viability and glycolysis and inhibits cisplatin chemosensitivity of laryngeal squamous cell carcinoma

Abstract

Laryngeal squamous cell carcinoma (LSCC) with a high incidence and mortality rate, has a serious impact worldwide. Phosphofructokinase-1 liver type (PFKL) is a major enzyme in glycolysis progress, but its role in modulating tumorigenesis and cisplatin (DDP) chemosensitivity of LSCC was still unclear. The mRNA and protein levels of PFKL were detected by qRT-PCR and immunohistochemical assay. Cell Counting Kit-8 assay and flow cytometry were carried out to observe cell viability, as well as apoptosis and mitochondrial reactive oxygen species (mito-ROS). Extracellular acidification rate and lactate content were measured using extracellular flux analysis and lactate assay kit. Immunofluorescent staining was used to evaluate the expression of γ-H2AX foci. DNA damage was detected via single-cell gel electrophoresis. Western blotting was introduced to evaluate the protein level of PFKL, LDHA, γ-H2AX, cleaved PARP, H3K27ac, and H3K9ac. Mice xenograft model of LSCC was built for in vivo validation. The PFKL expression was significantly increased in LSCC and associated with poor survival of LSCC patients. Knockdown of PFKL in LSCC cells significantly inhibited cell viability, ECAR, lactate content, and LDHA expression, but promoted mito-ROS level. Furthermore, knockdown of PFKL enhanced response of LSCC cells to DDP by increasing DDP-induced apoptosis, promoting DDP-induced mito-ROS level, γ-H2AX foci, tail DNA, and the expression of γ-H2AX and cleaved PARP. However, the overexpression of PFKL in LSCC cells had opposite experimental results. Nude mice tumor formation experiment proved that downregulation of PFKL significantly enhanced response of cells to DDP, demonstrated by reduced tumor volume, weight and increased TUNEL-positive cells. Suppression of CBP/EP300-mediated PFKL transcription inhibited cell viability and glycolysis and promoted mito-ROS in LSCC. PFKL promotes cell viability and DNA damage repair in DDP-treated LSCC through regulation of glycolysis pathway.