Effects of Long-Term Citrate Treatment in the PC3 Prostate Cancer Cell Line

Abstract

Acute administration of a high level of extracellular citrate displays an anti-proliferative effect on both in vitro and in vivo models. However, the long-term effect of citrate treatment has not been investigated yet. Here, we address this question in PC3 cells, a prostate-cancer-derived cell line. Acute administration of high levels of extracellular citrate impaired cell adhesion and inhibited the proliferation of PC3 cells, but surviving cells adapted to grow in the chronic presence of 20 mM citrate. Citrate-resistant PC3 cells are significantly less glycolytic than control cells. Moreover, they overexpress short-form, citrate-insensitive phosphofructokinase 1 (PFK1) together with full-length PFK1. In addition, they show traits of mesenchymal-epithelial transition: an increase in E-cadherin and a decrease in vimentin. In comparison with PC3 cells, citrate-resistant cells display morphological changes that involve both microtubule and microfilament organization. This was accompanied by changes in homeostasis and the organization of intracellular organelles. Thus, the mitochondrial network appears fragmented, the Golgi complex is scattered, and the lysosomal compartment is enlarged. Interestingly, citrate-resistant cells produce less total ROS but accumulate more mitochondrial ROS than control cells. Consistently, in citrate-resistant cells, the autophagic pathway is upregulated, possibly sustaining their survival. In conclusion, chronic administration of citrate might select resistant cells, which could jeopardize the benefits of citrate anticancer treatment.

Understanding the Central Role of Citrate in the Metabolism of Cancer Cells and Tumors: An Update

“…In this setting, an in vitro study reported the occurrence of a resistant clone of metastatic PCa cancer cells (PC3) under prolonged 10 mM citrate exposure (more than two weeks). This process was associated with a shorter PKF1 form (insensible to citrate regulation) and with the upregulation of autophagy [ 156 ]. Of note, this survival process—recycling superfluous molecules (proteins and lipids)—requires functional mitochondria for ATP production derived from FAO [ 157 ].…”

Early onset effects of single substrate accumulation recapitulate major features of LSD in patient-derived lysosomes

“…Lysosome distribution was quantified using Fiji software ( Caiazza et al., 2019 ). Individual cell ROIs were outlined and whole cell Lamp1 signal fluorescence was measured.…”

Advanced Technologies to Target Cardiac Cell Fate Plasticity for Heart Regeneration

“…Regardless of the reprogramming strategy, the acquisition of a new phenotype passes through the modification of gene regulatory networks of the resident cell type to fit the characteristics of the incoming target cell, in terms of cell behavior, proliferation, and metabolic rate [18]. These same changes can also be associated with some pathological cellular states, like tumorigenesis [19,20]. Therefore, adequate control of somatic cell plasticity is mandatory before reprogramming could be considered a useful tool for cardiac cell therapy and tissue engineering.…”