Cisplatin resistance remains a major problem in the treatment of lung cancer. We have discovered that cisplatin resistant (CR) lung cancer cells, regardless of the signaling pathway status, share the common parameter which is an increase in reactive oxygen species (ROS) and undergo metabolic reprogramming. CR cells were no longer addicted to the glycolytic pathway, but rather relied on oxidative metabolism. They took up twice as much glutamine and were highly sensitive to glutamine deprivation. Glutamine is hydrolyzed to glutamate for glutathione synthesis, an essential factor to abrogate high ROS via xCT antiporter. Thus, blocking glutamate flux using riluzole (an amyotropic lateral sclerosis approved drug) can selectively kill CR cells in vitro and in vivo. However, we discovered here that glutathione suppression is not the primary pathway in eradicating the CR cells. Riluzole can lead to further decrease in NAD+ (nicotinamide adenine dinucleotide) and lactate dehydrogenase-A (LDHA) expressions which in turn further heightened oxidative stress in CR cells. LDHA knocked-down cells became hypersensitive to riluzole treatments and possessed increased levels of ROS. Addition of NAD+ re-stabilized LDHA and reversed riluzole induced cell death. Thus far, no drugs are available which could overcome cisplatin resistance or kill cisplatin resistant cells. CR cells possess high levels of ROS and undergo metabolic reprogramming. These metabolic adaptations can be exploited and targeted by riluzole. Riluzole may serve as a dual-targeting agent by suppression LDHA and blocking xCT antiporter. Repurposing of riluzole should be considered for future treatment of cisplatin resistant lung cancer patients.

Despite numerous reports on immune checkpoint inhibitor for the treatment of non-small cell lung cancer (NSCLC), the response rate remains low but durable. Thus cisplatin still plays a major role in the treatment of NSCLC. While there are many mechanisms involved in cisplatin resistance, alteration in metabolic phenotypes with elevated levels of reactive oxygen species (ROS) are found in several cisplatin resistant tumors. These resistant cells become more reliant on mitochondria oxidative metabolism instead of glucose. Consequently, high ROS and metabolic alteration contributed to epithelial-mesenchymal transition (EMT). Importantly, recent findings indicated that EMT has a crucial role in upregulating PD-L1 expression in cancer cells. Thus, it is very likely that cisplatin resistance will lead to high expression of PD-L1/PD-1 which makes them vulnerable to anti PD-1 or anti PD-L1 antibody treatment. An understanding of the interactions between cancer cells metabolic reprogramming and immune checkpoints is critical for combining metabolism targeted therapies with immunotherapies.

Purpose/BackgroundThis study aimed to compare the frequency, clinical findings, treatment practices, and outcomes of toxicity to old-generation (OG) and new-generation (NG) antidepressants in our pediatric intensive care unit (PICU) by year-to-year.Methods/ProceduresThe study included patients hospitalized for antidepressant poisoning during the 11-year period of January 2010 through December 2020. Antidepressants were classified as OG and NG. The groups were compared in terms of patient demographic characteristics, type of poisoning (accidental/suicidal), clinical findings, supportive and extracorporeal treatments received, and outcomes.Findings/ResultsThe study included 58 patients (NG, n = 30; OG, n = 28). The median age of the patients was 178 months (range, 13.6–215 months) and 47 patients (81%) were female. Patients admitted for only antidepressant poisoning constituted 13.3% of all poisoning cases (58/436). Of these, 22 cases (37.9%) were accidental and 36 (62.3%) were suicidal. The most common cause of poisoning was amitriptyline (24/28) in the OG group and sertraline (13/30) in the NG group. Neurological symptoms were significantly more common in the OG group (76.2% vs 23.8%), while gastrointestinal involvement was more common in the NG group (82% vs 18%; P = 0.001 and P = 0.026, respectively). Old-generation antidepressant poisoning was associated with more frequent intubation (4 vs 0 patients, P = 0.048) and longer length of PICU stay (median, 1 day [range, 1–8] vs 1 day [range, 1–4], P = 0.019). Rates of therapeutic plasma exchange and intravenous lipid emulsion therapy did not differ (P = 0.483 and P = 0.229, respectively).Implications/ConclusionsIn poisoned patients, proper evaluation and management of patients requiring PICU admission are vital for favorable patient outcomes.

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