Tandem bispecific CD123/CLL-1 CAR-T cells exhibit specific cytolytic effector functions against human acute myeloid leukaemia.

OBJECTIVES: The treatment of refractory and recurrent acute myeloid leukaemia (AML) is still a challenge with poor response rates and short survival times. In an attempt to solve this problem, we constructed a tandem bispecific chimeric antigen receptor (CAR) targeting CD123 and C-type lectin-like molecule 1 (CLL-1), two different AML antigens, and verified its cytotoxic effects in vitro. METHODS: We established and cultured K562 cell lines expressing both CD123 and CLL1 antigens. Single-target CAR-T cells specific to CD123 and CLL1 were engineered, alongside tandem CD123/CLL1 bispecific CAR-T cells. Flow cytometry was used to determine cell phenotypes, transfection efficiencies, cytokine release, and CAR-T-cell proliferation, and an lactate dehydrogenase assay was used to detect the cytotoxicity of CD123/CLL-1 bispecific tandem CAR-T cells in vitro. RESULTS: Two types of tandem CAR-T cells exhibited significant killing effects on CLL-1 + CD123+ leukaemia cell lines and primary AML tumour cells. The killing efficiency of tandem CAR-T cells in the case of single antigen expression is comparable to that of single target CAR-T cells. When faced with dual target tumour cells, dual target CAR-T cells significantly surpass single target CAR-T cells. CD123/CLL-1 CAR-T cells in tandem targeted and killed CD123- and CLL-1-positive leukaemia cell lines and released a large number of cytokines. CONCLUSIONS: CD123/CLL-1 CAR-T cells in tandem can simultaneously target CD123 and CLL-1 on AML cells, demonstrating a significant ability to kill single antigens and multi-target tumour cells. This suggests that CD123/CLL-1 CAR-T cells exhibit significant advantages in the expression of multiple antigens in a wide range of target cells, which may help overcome the challenges posed by tumour heterogeneity and evasion mechanisms.

[Clinical Observation of Venetoclax Combined with Demethylating Agents on the Treatment of Relapsed/Refractory Acute Myeloid Leukemia].

OBJECTIVE: To investigate the efficacy and safety of venetoclax (VEN) combined with demethylating agents (HMA) in the treatment of relapsed/refractory acute myeloid leukemia (R/R AML). METHODS: The clinical data of 26 adult R/R AML patients who received the combination of VEN with azacitidine (AZA) or decitabine (DAC) in Huai'an Second People's Hospital from February 2019 to November 2021 were retrospectively analyzed. The treatment response, adverse events as well as survival were observed, and the factors of influencing the efficacy and survival were explored. RESULTS: The overall response rate (ORR) of 26 patients was 57.7% (15 cases), including 13 cases of complete response (CR) and CR with incomplete count recovery (CRi) and 2 cases of partial response (PR). Among the 13 patients who got CR/CRi, 7 cases achieved CRm (minimal residual disease negative CR) and 6 cases did not, with statistically significant differences in overall survival (OS) and event-free survival (EFS) between the two groups (P=0.044, 0.036). The median OS of all the patients was 6.6 (0.5-15.6) months, and median EFS was 3.4 (0.5-9.9) months. There were 13 patients in the relapse group and refractory group, respectively, with response rate of 84.6% and 30.8% (P=0.015). The survival analysis showed that the relapse group had a better OS than the refractory group (P=0.026), but there was no significant difference in EFS (P=0.069). Sixteen patients who treated for 1-2 cycles and 10 patients who treated for more than 3 cycles achieved response rates of 37.5% and 90.0%, respectively (P=0.014), and patients treated for more cycles had superior OS and EFS (both P<0.01). Adverse effects were mainly bone marrow suppression, complicated by various degrees of infection, bleeding, and gastrointestinal discomfort was common, but these could be all tolerated by patients. CONCLUSION: VEN combined with HMA is an effective salvage therapy for patients with R/R AML and is well tolerated by patients. Achieving minimal residual disease negativity is able to improve long-term survival of patients.

[The Clinical Features of Metabolic Syndrome in Receptors of Hematopoietic Stem Cells].

OBJECTIVE: To evaluate the incidence and clinical characteristics of metabolic syndrome (MS) within one year after hematopoietic stem cell transplantation (HSCT) in order to screen the risk factors for HSCT-MS, provide early intervention and improve the long-term quality of survival of patients. METHODS: The clinical follow-up data of 64 HSCT patients (survival time > 1 year) who received HSCT in our center from January 2007 to August 2018 were collected. Among them, 50 cases were allogeneic hematopoietic stem cell transplantation (allo-HSCT) and 14 cases were autologous hematopoietic stem cell transplantation (auto-HSCT). The changes of MS-related indexes and clinical characteristics before and 1, 3, 6 and 12 months after HSCT were analyzed retrospectively. RESULTS: In allo-HSCT group, 14 cases were diagnosed as MS before operation, including high-density lipoprotein cholesterol (hypo-HDL-C)> hyper triglycerides（hyper-TG）> hyper fasting glucose（hyper-FBG）> abdominal obesity (AO) > hypertension. The preoperative diagnosis of MS in the auto-HSCT group was 5 cases, in the order of hyper-FBG> hyper-TG> AO> hypo-HDL-C> hypertension. Incidence of MS at 1, 3, 6 and 12 months after transplantation: 19, 26, 24 and 20 cases in the allo-HSCT group, respectively; auto-HSCT group were 7, 7, 6 and 6 cases, respectively. Hyper-TG and hypo-HDL-C were prominent in both groups. CONCLUSION: The incidence of HSCT-MS is significantly higher within 1 year after HSCT. Regardless of allo-HSCT and auto-HSCT, the prevention and control of HSCT-MS is emphasized as an important guarantee to improve the long-term survival quality of HSCT patients.

Decitabine Compared With Conventional Regimens in Older Patients With Acute Myeloid Leukemia: A Meta-Analysis.

BACKGROUND: The incidence of acute myeloid leukemia (AML) increases with age. The overall prognosis remains poor for older patients. Studies on the efficacy of decitabine, an epigenetic agent, in older patients with AML have reported conflicting results. MATERIALS AND METHODS: For this meta-analysis, we performed a literature search and collected 38 studies (including 3298 patients with AML) to evaluate the role of decitabine in elderly patients with AML. We used complete response (CR) or overall response (OR) rate as indicators of effectiveness. RESULTS: Patients treated with decitabine have a higher CR/OR rate than those treated with low-dose cytarabine (CR, 2.60; 95% confidence interval [CI], 1.64-4.14; OR, 4.88; 95% CI, 1.98-12.04) or CAG/HAG (low-dose epirubicin and cytarabine with granulocyte stimulating factor/low-dose homoharringtonine and cytarabine with granulocyte stimulating factor) regimens (CR, 2.53; 95% CI, 1.98-3.23; OR, 2.89; 95% CI, 2.24-3.73). However, patients treated with decitabine had a CR rate equivalent to those treated with intensive chemotherapy (CR, 0.58; 95% CI, 0.28-1.22; P = .15). Use of decitabine in combination with other regimens resulted in a higher CR/OR rate than did use of decitabine alone (P < .001); there was no significant difference in infection rates and early death rates (P > .05). CONCLUSION: The findings presented in this article show that decitabine is effective and safe for the treatment of older patients with AML.

The D14 and R138 ion pair is involved in dimeric arginine kinase activity, structural stability and folding.

Arginine kinase (AK) is a key enzyme in cellular energy metabolism of invertebrates. There are two conserved amino acid residues D14 and R138 in dimeric AK which form inter-subunit hydrogen bond. In Stichopus japonicus AK, mutations in these residues caused pronounced loss of activity, conformational changes and distinct substrate synergism alteration. Mutations (R138G, R138A and D14G) abolished D14 and R138 interaction disrupted the structure or conformation of S. japonicus AK. These R138G, R138A and D14G mutations changed their native assembles of dimeric AK and caused them in a partially unfolded state. The partially unfolded state of these mutant AKs made them prone to aggregate under environmental stress. The D14E/R138K and R138K mutant AKs showed similar characteristics to those of WT AK for forming the interaction which could replacement roles of D14 and R138 interaction. These results suggested that D14 and R138 interaction is involved in AK's activity, substrate synergism and structural stability.

The effects of R683S (G) genetic mutations on the JAK2 activity, structure and stability.

Janus kinase 2 (JAK2) is an important mediator of cytokine receptor signaling and plays key roles in the hematopoietic and immune response. The acquired JAK2 R683S (G) mutations are presumed to be a biomarker for B-cell acute lymphoblastic leukemia (B-ALL). However, how these mutations leading to the B-ALL is still unclear. The crystal structure of JAK2 JH2 domain suggests that the residue R683 locating in the linker between the N and C lobes of JH2 domain is important for keeping the compact structure, activity and structural stability of this domain. Mutations R683S, R683G and R683E significantly increase JAK2 activity and decrease its structural stability. While the R683K and R683H mutations almost have no effects on the JAK2 activity and structural stability. Furthermore, the spectroscopic experiments imply that mutations R683S, R683G and R683E impair the structure of JAK2 JH2 domain, and lead JAK2 to partially unfolded state. It may be this partially unfolded state that caused JAK2 R683S (G) constitutive activation. This study provides clues in understanding the mechanism of JAK2 R683S (G) mutations caused B-ALL.