Chronic Ochratoxin A exposure induces pre-neoplastic transformation and metabolic reprogramming in normal kidney epithelial cells

Kidney is the primary target organ for Ochratoxin A (OTA)-induced carcinogenesis, yet the underlying mechanism(s) are unknown. Cancer cells undergo various metabolic reprogramming. Hence, we assessed the effect of low-dose OTA on pre-neoplastic changes and metabolic perturbations in NRK52E cells. Cells were exposed to OTA for 2 months (sub-chronic) and 4 months (chronic), and various pre-neoplastic properties were evaluated using different cell-based assays, such as soft agar, clonogenic, wound healing, and ATP determination assay. Additionally, NMR-based metabolomic profiling was performed to assess OTA-induced metabolic perturbations in NRK52E cells and the involvement of key metabolites in OTA-induced cellular transformation. OTA exposure resulted in pronounced induction of cell survival, proliferation, and migration at both exposure durations in NRK52E cells, with more significant effects observed after 4 months of chronic exposure. Further, metabolomics study showed significant metabolic perturbations in NRK52E cells following chronic exposure to OTA. Notably, lactate emerged as the most important altered metabolite among those identified. Furthermore, exogenous lactate exposure to NRK52E cells induced pronounced pre-neoplastic changes similar to those observed in OTA-transformed cells. Collectively, this study showed that chronic OTA exposure caused pre-neoplastic transformations in NRK52E cells and suggests that lactate may play a crucial role in OTA-induced cellular transformation.