Abstract: Objective To investigate the role of long non-coding RNA (lncRNA) BCYRN1 in activation of glycolysis in extranodal NK/T-cell lymphoma (ENKTCL)  and its mechanism. Methods The data of 236 ENKTCL patients who were diagnosed and treated in Beijing Tongren Hospital from 2010 to 2021 were collected to analyze the correlation between fasting blood glucose (FBG) and progression-free survival (PFS). The content of BCYRN1 in the 32 newly diagnosed ENKTCL patients was detected by qRT-PCR, and the correlation between BCYRN1 and PFS was analyzed. The SNK-6 cell lines with overexpression of BCYRN1 (OE-BCYRN1 group) and interference of BCYRN1 (shBCYRN1 group) were constructed by the plasmid transfection method. The Screen Quest- colorimetric method was used to detect glucose uptake, and lactate production was detected by Lactic Acid assay kit. The expression levels of PKM2, HIF-1α, SLC2A1, LDHA and PDK1 were detected by qRT-PCR and Western blot, and the protein synthesis inhibitor, lysosomal inhibitor or activator were added to observe the effect of BCYRN1 on PKM2 stability. The RNA pull-down and RIP experiments were used to determine the interaction mode between BCYRN1 and PKM2. Results Among 236 ENKTCL patients, 49 were in the hyperglycemia group (FBG>5.6 mmol/L) and 187 were in the normal group (FBG≤5.6 mmol/L). The 5-year PFS rate in the hyperglycemia group was lower than that in the hypoglycemia group (32.1% vs 63.7%, P<0.001). The 3-year PFS in the high BCYRN1 expression group was lower than that in the low expression group ( 26.1% vs 82.5%, P=0.014). After interference with BCYRN1, the glucose intake and lactate production level of ENKTCL SNK-6 cells were significantly decreased (all P<0.05). After overexpression of BCYRN1, the expression levels of PKM2, HIF-1α, SLC2A1, LDHA and PDK1 were significantly increased (all P<0.05). After treatment of SNK-6 cells with protein synthesis inhibitor (Cycloheximide) for 3 h or 6 h, the degradation rate of PKM2 in OE-BCYRN1 group was significantly lower than that in OE-CTRL group (all P<0.05), and the degradation ratio of PKM2 in the shBCYRN1 group was significantly higher than that in the shCTRL group. After lysosomal inhibitor (Leupeptin) treatment, PKM2 degradation ratio in shBCYRN1+Leupeptin group decreased significantly (P<0.01); while the degradation ratio of PKM2 in OE-BCYRN1+6-AN group was significantly increased after treatment with lysosome activator (6-Aminonicotinamide)(P<0.01). The RNA pull-down and RIP experiments showed that BCYRN1 gene could interact directly with PKM2 protein. Conclusions BCYRN1 may activate ENKTCL glycolysis pathway by up-regulating PKM2 expression through the lysosomal pathway.

Key words: Extranodal NK/T-cell lymphoma, Glycolysis pathway, Long non-coding RNA, BCYRN1, PKM2