AKR1C1 promotes non-small cell lung cancer proliferation via crosstalk between HIF-1α and metabolic reprogramming

AKR1B1 Inhibits Ferroptosis and Promotes Gastric Cancer Progression via Interacting With STAT3 to Activate SLC7A11

Gastric cancer (GC) is a frequently diagnosed malignant tumor in clinical settings; however, the mechanisms underlying its tumorigenesis remain inadequately understood. In this study, we identified significantly elevated expression levels of AKR1B1 in GC tissues through quantitative polymerase chain reaction (qPCR) and western blotting assays. Furthermore, a negative correlation was established between patient survival probability and AKR1B1 expression levels. Functionally, our experiments, including colony formation, transwell migration, and xenograft assays, demonstrated that the depletion of AKR1B1 inhibited the proliferation and progression of GC cells both in vivo and in vitro. Additionally, the assessment of reactive oxygen species (ROS), malondialdehyde (MDA), glutathione (GSH), and mitochondrial morphology confirmed that AKR1B1 depletion induces ferroptosis. Mechanistically, we found that AKR1B1 interacts with STAT3, which subsequently activates SLC7A11. Notably, the ferroptosis induced by AKR1B1 depletion could be reversed by the overexpression of SLC7A11, thereby substantiating these interactions. In conclusion, our findings identify AKR1B1 as a novel oncogene in GC and elucidate the mechanism involving the AKR1B1-STAT3-SLC7A11 pathway and ferroptosis, providing new insights for potential therapeutic strategies in the treatment of GC.

AKR1C1 protects against intracerebral hemorrhage by suppressing neuronal cell death via the P53/SLC7A11/GPX4 axis

Intracerebral hemorrhage (ICH) is associated with the highest rates of mortality and residual disability. To date, effective treatments to delay or prevent ICH are still lacking. Multiple forms of neuronal cell death have been discovered following ICH, including apoptosis, necrosis, autophagy, and ferroptosis. Aldo-keto reductase family 1 member C1 (AKR1C1) has been identified to act as a protective factor in ferroptosis. However, whether AKR1C1 was involved in the development of ICH was unknown. In this study, the left cerebral striatum of the Sprague-Dawley rat was injected with collagenase type IV to induce an in vivo model. Primary rat cortical neurons treated with oxygen hemoglobin (OxyHb) were applied to as an in vitro model. AKR1C1 was found to be downregulated and immunoreactivity colocalized with NeuN-positive neurons in the perihematomal region. Rats injected with lentiviral particles overexpressing AKR1C1 showed the reduction of cerebral hematoma and the remission of blood-brain barrier disruption. Moreover, AKR1C1 upregulation repressed cell apoptosis and ferroptosis induced by ICH through downregulating the expression of pro-apoptotic factors, inhibiting iron accumulation and lipid peroxidation, along with increasing the expression of solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4). The results of in vitro assays were consistent with results from the in vivo. Mechanistically, P53 overexpression augmented the cellular damage in OxyHb-stimulated neurons when AKR1C1 was overexpressed. Taken together, AKR1C1 improves ICH injury by inhibiting neuronal cell death via negatively regulating P53 expression and affecting the SLC7A11/GPX4 pathway.

Hypoxia-Inducible Factor-1α Regulates BNIP3-Dependent Mitophagy and Mediates Metabolic Reprogramming Through Histone Lysine Lactylation Modification to Affect Glioma Proliferation and Invasion

OBJECTIVE

Gliomas are the predominant form of malignant brain tumors. We investigated the mechanism of hypoxia-inducible factor-1α (HIF-1α) affecting glioma metabolic reprogramming, proliferation and invasion.

METHODS

Human glioma cell U87 was cultured under hypoxia and treated with small interfering (si)HIF-1α, si-B cell lymphoma-2/adenovirus E1B 19-kDa interacting protein 3 (siBNIP3), si-YT521-B homology domain 2 (siYTHDF2), 3-methyladenine and 2-deoxyglucose, with exogenous sodium lactate-treated normally-cultured cells as a lactate-positive control. Cellular hexokinase 2, lactate dehydrogenase A and pyruvate dehydrogenase kinase 1 enzyme activities, glucose uptake, and levels of lactic acid and adenosine triphosphate (ATP), and HIF-1α, glycolysis-related proteins, mitophagy-related proteins, histone H3 lysine 18 lactylation (H3K18la) and YTHDF2 were determined by ELISA, 2-NBDG, kits, and Western blot. Extracellular acidification rate (ECAR), and cell proliferation, invasion, apoptosis and mitophagy were evaluated by extracellular flux analysis, CCK-8, Transwell, flow cytometry, and immunofluorescence staining. H3K18la-YTHDF2 relationship and YTHDF2-BNIP3 interaction were assessed by ChIP and Co-IP assays.

RESULTS

Hypoxia-induced highly-expressed HIF-1α in glioma cells increased glycolysis-related protein levels, glycolytic enzyme activities, glucose uptake, lactic acid production, ATP level and ECAR, thereby promoting metabolic reprogramming, invasion and proliferation. HIF-1α mediated metabolic reprogramming, proliferation and invasion through BNIP3-dependent mitophagy, which were partly negated by mitophagy inhibition. HIF-1α induced histone Kla modification to upregulate YTHDF2. YTHDF2 downregulation impeded YTHDF2-BNIP3 interaction and inhibited HIF-1α-induced BNIP3-dependent mitophagy, curbing glioma cell metabolic reprogramming, proliferation and invasion.

CONCLUSIONS

Hypoxia-induced high HIF-1α expression upregulated YTHDF2 through hH3K18la modification, enhanced YTHDF2-BNIP3 interaction, and regulated BNIP3-dependent mitophagy-mediated metabolic reprogramming to affect glioma proliferation and invasion.

Effects of KEAP1 Silencing on NRF2 and NOTCH Pathways in SCLC Cell Lines

The KEAP1/NRF2 pathway is a master regulator of several redox-sensitive genes implicated in the resistance of tumor cells against therapeutic drugs. The dysfunction of the KEAP1/NRF2 system has been correlated with neoplastic patients' outcomes and responses to conventional therapies. In lung tumors, the growth and the progression of cancer cells may also involve the intersection between the molecular NRF2/KEAP1 axis and other pathways, including NOTCH, with implications for antioxidant protection, survival of cancer cells, and drug resistance to therapies. At present, the data concerning the mechanism of aberrant NRF2/NOTCH crosstalk as well as its genetic and epigenetic basis in SCLC are incomplete. To better clarify this point and elucidate the contribution of NRF2/NOTCH crosstalk deregulation in tumorigenesis of SCLC, we investigated genetic and epigenetic dysfunctions of the KEAP1 gene in a subset of SCLC cell lines. Moreover, we assessed its impact on SCLC cells' response to conventional chemotherapies (etoposide, cisplatin, and their combination) and NOTCH inhibitor treatments using DAPT, a γ-secretase inhibitor (GSI). We demonstrated that the KEAP1/NRF2 axis is epigenetically controlled in SCLC cell lines and that silencing of KEAP1 by siRNA induced the upregulation of NRF2 with a consequent increase in SCLC cells' chemoresistance under cisplatin and etoposide treatment. Moreover, KEAP1 modulation also interfered with NOTCH1, HES1, and DLL3 transcription. Our preliminary data provide new insights about the downstream effects of KEAP1 dysfunction on NRF2 and NOTCH deregulation in this type of tumor and corroborate the hypothesis of a cooperation of these two pathways in the tumorigenesis of SCLC.

NEAT1_1 confers gefitinib resistance in lung adenocarcinoma through promoting AKR1C1-mediated ferroptosis defence

Gefitinib is one of the most extensively utilized epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) for treating advanced lung adenocarcinoma (LUAD) patients harboring EGFR mutation. However, the emergence of drug resistance significantly compromised the clinical efficacy of EGFR-TKIs. Gaining further insights into the molecular mechanisms underlying gefitinib resistance holds promise for developing novel strategies to overcome the resistance and improve the prognosis in LUAD patients. Here, we identified that the inhibitory efficacy of gefitinib on EGFR-mutated LUAD cells was partially dependent on the induction of ferroptosis, and ferroptosis protection resulted in gefitinib resistance. Among the ferroptosis suppressors, aldo-keto reductase family 1 member C1 (AKR1C1) exhibited significant upregulation in gefitinib-resistant strains of LUAD cells and predicted poor progression-free survival (PFS) and overall survival (OS) of LUAD patients who received first-generation EGFR-TKI treatment. Knockdown of AKR1C1 partially reversed drug resistance by re-sensitizing the LUAD cells to gefitinib-mediated ferroptosis. The decreased expression of miR-338-3p contributed to the aberrant upregulation of AKR1C1 in gefitinib-resistant LUAD cells. Furthermore, upregulated long non-coding RNA (lncRNA) nuclear paraspeckle assembly transcript 1_1 (NEAT1_1) sponged miR-338-3p to neutralize its suppression on AKR1C1. Dual-luciferase reporter assay and miRNA rescue experiment confirmed the NEAT1_1/miR-338-3p/AKR1C1 axis in EGFR-mutated LUAD cells. Gain- and loss-of-function assays demonstrated that the NEAT1_1/miR-338-3p/AKR1C1 axis promoted gefitinib resistance, proliferation, migration, and invasion in LUAD cells. This study reveals the effects of NEAT1_1/miR-338-3p/AKR1C1 axis-mediated ferroptosis defence in gefitinib resistance in LUAD. Thus, targeting NEAT1_1/miR-338-3p/AKR1C1 axis might be a novel strategy for overcoming gefitinib resistance in LUAD harboring EGFR mutation.

Expression of AKRs superfamily and prognostic in human gastric cancer

The human aldo-keto reductase (AKRs) superfamily is involved in the development of various tumors. However, the different expression patterns of AKRs and their prognostic value in gastric cancer (GC) have not been clarified. In this study, we analyzed the gene expression and gene methylation level of AKRs in GC patients and the survival data and immune infiltration based on AKRs expression, using data from different databases. We found that the expression levels of AKR1B10, AKR1C1, AKR1C2, and AKR7A3 in GC tissues were lower and the expression level of AKR6A5 was higher in GC tissues than in normal tissue. These differentially expressed genes (AKR1B10, AKR1C1, AKR1C2, AKR7A3, and AKR6A5) were significantly correlated with the infiltration level. The expression of SPI1 and AKR6A5 in GC was positively correlated. Survival analysis showed that GC levels of AKR6A5 reduced or increased mRNA levels of AKR7A3, and AKR1B10 was expected to have higher overall survival (OS), first progression (FP) survival, and postprogression survival (PPS) rates and a better prognosis. Moreover, the expression of AKR1B1 was found to be correlated with the staging of GC. The methylation of AKR6A5 (KCNAB2) at cg05307871 and cg01907457 was significantly associated with the classification of GC. Meta-analysis and ROC curve analysis show that the expression level of AKR1B1 and the methylation of cg16156182 (KCNAB1), cg11194299 (KCNAB2), cg16132520 (AKR1B1), and cg13801416 (AKR1B1) had a high hazard ratio and a good prognostic value. These data suggest that the expression and methylation of AKR1B1 and AKR6A5 are significantly related to the prognosis.