Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) positively affect the initial control of non-small cell lung cancer (NSCLC). Rapidly acquired resistance to EGFR-TKIs is a major hurdle in successful treatment. However, the mechanisms that control the resistance of EGFR-TKIs remain largely unknown. RNA structures have widespread and crucial functions in many biological regulations; however, the functions of RNA structures in regulating cancer drug resistance remain unclear. Here, the psoralen analysis of RNA interactions and structures (PARIS) method is used to establish the higher-order RNA structure maps of EGFR-TKIs-resistant and -sensitive cells of NSCLC. Our results show that RNA structural regions are enriched in untranslated regions (UTRs) and correlate with translation efficiency (TE). Moreover, yrdC N⁶-threonylcarbamoyltransferase domain containing (YRDC) promotes resistance to EGFR-TKIs. RNA structure formation in YRDC 3' UTR suppresses embryonic lethal abnormal vision-like 1 (ELAVL1) binding, leading to EGFR-TKI sensitivity by impairing YRDC translation. A potential therapeutic strategy for cancer treatment is provided using antisense oligonucleotide (ASO) to perturb the interaction between RNA and protein. Our study reveals an unprecedented mechanism through which the RNA structure switch modulates EGFR-TKI resistance by controlling YRDC mRNA translation in an ELAVL1-dependent manner.
Humans ; Carcinoma, Non-Small-Cell Lung/genetics* ; Cell Line, Tumor ; Drug Resistance, Neoplasm/genetics* ; ErbB Receptors/metabolism* ; GTP-Binding Proteins/therapeutic use* ; Lung Neoplasms/genetics* ; Mutation ; Protein Kinase Inhibitors/therapeutic use* ; RNA ; RNA-Binding Proteins/genetics* ; Tyrosine Kinase Inhibitors/therapeutic use*

Objective To explore any protective effect of hyperbaric oxygen in traumatic brain injury and its effect on the expression of silent information regulator 1 ( SIRT1) . Methods Sixty mice were randomly divided into a control group (n=20), a brain injury group (TBI, n=20) and a hyperbaric oxygen therapy group (TBI+HBO, n=20) . The mice in the TBI and TBI + HBO groups were given massive blows to establish closed brain injuries, while in the control group the scalp was incised and a bone window was removed without brain damage. The mice in the TBI + HBO group were given hyperbaric oxygen treatment twice per day for five days, while those in the TBI and control groups were put in the hyperbaric chamber but not given HBO treatment. At one hour after the trauma and on 5 days afterward, the neurological functioning of the mice was measured to generate neurological severity scores. Brain tissue was resected for triphenyl tetrazolium staining to measure the infarct area. Cortical neurons were isolated to eval-uate the SIRT1 expression using immunofluorescence and Western blotting. Results No significant difference in the average NSS score was observed between the TBI and TBI+HBO groups one hour after modeling. The average NSS score in the TBI group subsequently increased and then decreased gradually until the fifth day. The average NSS score of the TBI+HBO group was significantly lower than that of the TBI group after the onset of the treatment at the differ-ent time points, decreasing to (2.11±0.43) on the 5thday compared with (4.06±0.54) in the TBI+HBO group. On the 2nd day after the trauma, the cerebral infarction areas of the TBI and TBI+HBO groups were significantly larger than in the control group. During the treatment, the infarction area of the TBI+HBO group decreased gradually until on the 5th day it was significantly smaller than that of the TBI group. Traumatic brain injury significantly down-regula-ted SIRT1 protein compared with the control group, but the hyperbaric oxygen therapy significantly increased the ex-pression of SIRT1 compared with the TBI group. Conclusion Hyperbaric oxygen therapy can significantly relieve traumatic brain injury, reducing NSS scores and the infarcted area and enhancing SIRT1 expression, at least in mice.

Objective To develop a method for the determination of ganciclover in human plasma by RPHPLC.Methods Plasma containing ganciclover was extracted with methanol and methylene chloride,qualitative and quantitative analysis was carried out directly.Working curve,linear range,recovery,precision and so on was obtained according to the sample pre-processing method and analysis state.The HPLC method has been taken to investigate the plasma concentration of ganciclover for 12 volunteers.Results The relationship of the peak area of ganciclover concentration in plasma linear within the range of 0.05 μg/mL～1.60 μg/mL(r=0.9999).The lowest detection limit was 0.01 μg/mL(S/N≥13).The intra and inter-day RSD were less than 5.1%respectively.The recovery is about 90.0%～95.4%.Conclusion The established method in the article was shown to be sensitive,accurate and simple for the determination of ganciclover level.It is suitable for clinical detection of ganciclover and forensic medicine and toxicology analysis.