Mechanism Of Venetoclax Resistance In Novel Acute Myeloid Leukemia

Objective:In this study,patients with acute myeloid leukemia(AML)treated with venetoclax(Ven)were clinically observed to determine the effect of different genetic backgrounds on Ven treatment of AML patients.To determine the abnormal expression of BCL-2 family proteins in Ven sensitive and resistant AML patients;The activation status of iron death in Ven treated AML patients was determined by detecting iron-death regulatory factor GPX4,ferritin and iron ion in drug-resistant and sensitive leukemia patients.To explore whether the iron death pathway could be a potential mechanism for controlling drug resistance of Venecra in the treatment of myeloid leukemia.Method:1)The efficacy of Ven was evaluated in AML patients after two courses of Ven treatment,and bone marrow blood samples of AML patients were collected at the initial treatment state and after two courses of treatment,and single leukemia cells were extracted and sorted into leukemia cells labeled CD117,CD33,CD13 and MPO by flow cytometry.The expression levels of Bcl-2,MCL-1 and BCL-1 in leukemia cells before and after Ven treatment were measured by Western blot.2)WB,enzyme-linked immunoassay and colorimetry were used to detect the levels of iron-death inhibiting protein GPX4 and activating condition factor serum ferritin(SF)and Fe2+in leukemia cells of AML patients after initial treatment and Ven treatment,and the contents of GPX4 protein,serum ferritin and iron ion in AML patients of each Ven treatment group were analyzed.To predict the status of iron death in Ven treated groups.Results:1)In each genetic risk stratification,the mean PFS of Ven patients in the medium-low risk group was 21.5 months,compared with the mean PFS of high risk group was 17.7 months(P <0.05).The average PFS of Ven patients with AML in Ven treatment sensitive group was 24 months,compared with the average PFS of Ven treatment resistant group was 14.2 months(P< 0.05).2)In the genetic risk groups,the protein contents of MCL-1 and BCL-1 in AML patients after Ven treatment were higher than those in AML patients with initial treatment(P < 0.05);The content of Bcl-2 protein in AML cells after Ven treatment was lower than that in initially treated AML cells(P < 0.05).There was no significant difference in BCL-2 family subproteins between high risk group and low risk group(P > 0.05).3)The protein contents of MCL-1 and BCL-1 in leukemia cells of Ven patients with sensitive and drug-resistant AML were higher than those in leukemia cells of patients with initial state AML(P < 0.05).Moreover,the content of Bcl-2 protein in AML cells after Ven treatment was lower than that in AML cells with initial state(P < 0.05).Meanwhile,the content of MCL-1 protein in leukemia cells of Ven resistant AML patients was higher than that of sensitive AML patients(P < 0.05).However,BCL-1 and Bcl-2 proteins were not statistically significant in Ven treatment sensitive and drug resistant groups.4)In all genetic risk groups,the contents of ferritin and iron ion in serum of Ven treated AML patients were higher than those in initial AML patients(P < 0.05).However,GPX4 protein was decreased in AML cells after Ven treatment,and the contents of GPX4,ferritin and iron ion in the cells and serum of AML patients in Ven treatment sensitive and drug resistant groups were higher than those in initially treated leukemia cells(P < 0.05).Meanwhile,the contents of ferritin and GPX4 protein in serum and cells of AML patients in drug-resistant group were higher than those in sensitive group(P < 0.05).However,the serum iron content of AML patients in sensitive group was higher than that in drug-resistant group(P < 0.05).Conclusion:1)Genetically moderate and low-risk AML patients after Ven treatment had a significant survival advantage.2)Genetic background does not interfere with the expression of BCL-2 family proteins in Ven treated AML patients;3)After Ven treatment,the expression of Bcl-2 protein remained low in both drug-resistant and sensitive groups,while the expression level of MCL-1 protein increased compared with the initial treatment.Moreover,the expression of MCL-1 protein in the drug-resistant group was significantly higher than that in the sensitive group,so Mc L-1 protein may play a role in the generation of AML resistance after Ven treatment.4)The expression of GPX4 and ferritin was high and the content of iron ion was low in Ven resistant AML patients,while the expression of GPX4 and ferritin was low and the content of iron ion was high in white blood patients in Ven treatment sensitive group,suggesting that high expression of MCL-1 in drug-resistant leukemia inhibited iron death activity.Iron death was active in the sensitive group with relatively low expression of MCL-1.