Combined Time Restricted Feeding and Cisplatin Enhance the Anti-tumor Effects in Cisplatin Resistant and -Sensitive Lung Cancer Cells

Combination therapy as an important treatment option for lung cancer has been attracting attention due to the primary and acquired resistance of chemotherapeutic drugs in the clinical application. In the present study, as a new therapy strategy, concomitant treatment with time-restricted feeding (TRF) plus cisplatin (DDP) on lung cancer growth was investigated in DDP-resistant and DDP-sensitive lung cancer cells. We first found that TRF significantly enhanced the drug susceptibility of DDP in DDP-resistant A549 (A549/DDP) cell line, illustrated by reversing the inhibitory concentration 50 (IC50) values of A549/DDP cells to normal level of parental A549 cells. We also found that TRF markedly enhanced DDP inhibition on cell proliferation, migration, as well as promoted apoptosis compared to the DDP-alone group in A549, H460 and A549/DDP cells lines. We further revealed that the synergistic anti-tumor effect of combined DDP and TRF was greater than that of combined DDP and simulated fasting condition (STS), a known anti-tumor cellular medium. Moreover, mRNA sequence analysis from A549/DDP cell line demonstrated the synergistic anti-tumor effect involved in upregulated pathways in p53 signaling pathway and apoptosis. Notably, compared with the DDP-alone group, combination of TRF and DDP robustly upregulated the P53 protein expression without mRNA level change by regulating its stability via promoting protein synthesis and inhibiting degradation, revealed by cycloheximide and MG132 experiments. Collectively, our results suggested that TRF in combination with cisplatin might be an additional novel therapeutic strategy for patients with lung cancer Overall design: The three different interventions were as follows: RPMI-1640 medium (Gibco, USA) continually supplemented with 2 g/L glucose and 10% FBS as a normal control (CON) diet for 24h cycles; Normal control RPMI-1640 medium for 6 h followed with serum-free and glucose-free RPMI-1640 medium for 18 h for 24h cycles as a TRF mimicking group; 0.5 g/L glucose and 1% FBS were continuously added to glucose-free RPMI-1640 medium as a simulated fasting condition (STS) for 24h cycles. When changing the medium, cells were washed twice with PBS and then switched to another medium.