Bladder cancer cells prevent cisplatin-induced oxidative stress by upregulating Nestin1 expression

Redox adaptation plays a critical role in cancer cells' drug tolerance and sensitivity. The antioxidative response is induced by nuclear factor erythroid 2-related factor 2 (Nrf2), which triggers the transcriptional activation of genes related to chemosensitivity, glutathione synthesis, and cell protection. Although Nestin1 is known to regulate cellular redox homeostasis by regulating Nrf2 in lung cancer cells, its regulatory effect on the antioxidative state of bladder cancer (BC) cells remains unclear.

The oxidative stress levels in two cisplatin-treated BC cell lines (T24 and J82) were examined using 2',7'-dichlorofluorescin diacetate staining and real-time quantitative reverse transcription-PCR (RT-qPCR) assays. The cell viability, growth, and apoptosis were determined using CCK-8, colony formation, and flow cytometric assays, respectively. The mRNA and protein levels of Nestin1, Nrf2, and several antioxidant enzymes were quantified using RT-qPCR and western blot assays. A mouse xenograft model was used to determine the effect of Nestin1 on the T24 tumor growth in vivo.

Cisplatin treatment induced reactive oxygen species (ROS) generation and antioxidative damage in the T24 and J82 cells, reducing their viability and growth and triggering their apoptosis. Moreover, the Nestin1 and Nrf2 protein levels were enhanced in both treated cell lines. Loss- and gain-of-function assays indicated that Nestin1 expression was positively correlated with the Nrf2 protein expression in the BC cells. Nestin1 overexpression reduced the ROS generation, alleviated the redox disorder, promoted cell viability, and reduced apoptosis, but its silencing had the opposite effects. Importantly, Nestin1 overexpression enhanced the chemoresistance of BC cells to cisplatin in vivo, but its knockdown improved the chemosensitivity of the cells and increased their apoptosis.

These results provide a theoretical basis for further targeting the transcription factors, including Nestin1 and Nrf2, in the treatment of BC with cisplatin.