Intravenous arsenic trioxide and all-trans retinoic acid as front-line therapy for low-risk acute promyelocytic leukemia

Predictors of early death and clinical features in newly diagnosed patients with low-intermediate risk acute promyelocytic leukemia

Background

Although most acute promyelocytic leukemia(APL) with low-intermediate risk could survive the induction treatment, early death still a big problem to have effects on overall survival in real world.This study aimed to analyze the clinical characteristics and possible predictors of early death in newly diagnosed patients with low-intermediate-risk acute promyelocytic leukemia.

Methods

Sixty patients with newly diagnosed low/intermediate-risk APL admitted to Mianyang Central Hospital from January 2013 to December 2021 were retrospectively analyzed.

Results

Sixty patients with a median age of 46 years (range, 17-75 years) were included. Fourteen patients (23.3%) were in low-risk group, and 46 patients (76.7%) were in intermediate-risk group. Fourteen patients (23.3%) died during induction treatment. Five patients died of hemorrhage, 5 of severe infection and 4 of differentiation syndrome. Multivariate analysis showed that HGB <65g/L at diagnosis (OR=38.474, 95%CI: 2.648~558.923, P=0.008) during induction treatment was an independent risk factors for early death in low- intermediate risk APL patients. In survival group, all patients achieved complete remission, the time to achieve remission was 25.87 ± 5.02 days, the average ATO dosage was 0.16 ± 0.03 mg/kg/day. In univariate analysis, there was no statistically significant difference in time span for remission when ATO dosage was in the 0.11~0.16mg/kg/day range. Compared with patients with low-risk APL, those with intermediate-risk APL had higher white blood cell counts (at diagnosis, day 3, day 5 and peak), higher level of lactate dehydrogenase, higher percentage of bone marrow promyelocytes, more platelet transfusions during treatment, and more early deaths (P<0.05). The overall survival of intermediate-risk APL patients seemed worse than those with low-risk APL (χ=5.033, P =0.025).

Conclusions

In patients with low-intermediate risk APL, HGB <65g/L at diagnosis was an independent risk factors for early death. Remission could still be achieved at low-dose ATO without affecting the required time for low-intermediate risk APL patients. Differences in clinical characteristics were found between low-risk and intermediate-risk APL. The intermediate-risk group had higher early mortality risk than the low-risk group.

Preclinical In Vitro Model to Assess the Changes in Permeability and Cytotoxicity of Polarized Intestinal Epithelial Cells during Exposure Mimicking Oral or Intravenous Routes: An Example of Arsenite Exposure

The gastrointestinal tract (GIT) is exposed to xenobiotics, including drugs, through both: local (oral) and systemic routes. Despite the advances in drug discovery and in vitro pre-clinical models, there is a lack of appropriate translational models to distinguish the impact of these routes of exposure. Changes in intestinal permeability has been observed in different gastrointestinal and systemic diseases. This study utilized one such xenobiotic, arsenic, to which more than 200 million people around the globe are exposed via their food, drinking water, work environment, soil, and air. The purpose of this study was to establish an in vitro model to mimic gastrointestinal tract exposure to xenobiotics via oral or intravenous routes. To achieve this, we compared the route (mimicking oral and intravenous exposure to GIT and the dose response (using threshold approach) of trivalent and pentavalent inorganic arsenic species on the permeability of in vitro cultured polarized T84 cells, an example of intestinal epithelial cells. Arsenic treatment to polarized T84 cells via the apical and basolateral compartment of the trans-well system reflected oral or intravenous routes of exposure in vivo, respectively. Sodium arsenite, sodium arsenate, dimethyl arsenic acid sodium salt (DMA^V), and disodium methyl arsonate hydrate (MMA^V) were assessed for their effects on intestinal permeability by measuring the change in trans-epithelial electrical resistance (TEER) of T-84 cells. Polarized T-84 cells exposed to 12.8 µM of sodium arsenite from the basolateral side showed a marked reduction in TEER. Cytotoxicity of sodium arsenite, as measured by release of lactate dehydrogenase (LDH), was increased when cells were exposed via the basolateral side. The mRNA expression of genes related to cell junctions in T-84 cells was analyzed after exposure with sodium arsenite for 72 h. Changes in TEER correlated with mRNA expression of focal-adhesion-, tight-junction- and gap-junction-related genes (upregulation of Jam2, Itgb3 and Notch4 genes and downregulation of Cldn2, Cldn3, Gjb1, and Gjb2). Overall, exposure to sodium arsenite from the basolateral side was found to have a differential effect on monolayer permeability and on cell-junction-related genes as compared to apical exposure. Most importantly, this study established a preclinical human-relevant in vitro translational model to assess the changes in permeability and cytotoxicity during exposure, mimicking oral or intravenous routes.

Inhibition of mitochondrial complex III induces differentiation in acute myeloid leukemia

Although acute myeloid leukemia (AML) is a highly heterogeneous disease with diverse genetic subsets, one hallmark of AML blasts is myeloid differentiation blockade. Extensive evidence has indicated that differentiation induction therapy represents a promising treatment strategy. Here, we identified that the pharmacological inhibition of the mitochondrial electron transport chain (ETC) complex III by antimycin A inhibits proliferation and promotes cellular differentiation of AML cells. Mechanistically, we showed that the inhibition of dihydroorotate dehydrogenase (DHODH), a rate-limiting enzyme in de novo pyrimidine biosynthesis, is involved in antimycin A-induced differentiation. The activity of antimycin A could be reversed by supplement of excessive amounts of exogenous uridine as well as orotic acid, the product of DHODH. Furthermore, we also found that complex III inhibition exerts a synergistic effect in differentiation induction combined with DHODH inhibitor brequinar as well as with the pyrimidine salvage pathway inhibitor dipyridamole. Collectively, our study uncovered the link between mitochondrial complex III and AML differentiation and may provide further insight into the potential application of mitochondrial complex III inhibitor as a mono or combination treatment in differentiation therapy of AML.

Development and validation of a droplet digital PCR assay for the evaluation of PML-RARα fusion transcripts in acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) is an aggressive disease that requires prompt treatment. Promyelocytic leukemia protein-retinoic acid receptor α (PML-RARα) fusion genes resulting from reciprocal translocation are considered a molecular basis for diagnosing APL. Moreover, PML-RARα fusion gene testing is an essential tool for monitoring the response to therapy via minimal residual disease and providing a diagnosis before rapid disease progression in APL. The present study developed a novel droplet digital PCR (ddPCR) assay to rapidly detect two PML-RARα variants (bcr1 and bcr3) and compared its limit of detection (LOD) with quantitative PCR (qPCR). It was demonstrated that the LOD of ddPCR for PML-RARα reached 0.001%, and the evaluation of high copy number samples of PML-RARα by ddPCR correlated well with qPCR. Furthermore, clinical sample testing with ddPCR found that 34 and 24% samples were bcr-1-positive and bcr3-positive, respectively. However, according to qPCR, 30% of the samples were bcr1-positive and 20% were bcr3-positive. In addition, the concordance rate between ddPCR and qPCR reaction was 86%. While monitoring minimal residual disease, the PML-RARα mutation rate of three patients who recovered well decreased to 0.34%. However, one patient who was bcr3-positive and relapsed had a mutation rate of 13% while in remission, indicating that the bcr3 isoform may be an adverse prognostic factor affecting recovery. Therefore, the present results suggested that this novel ddPCR assay may be useful for monitoring and evaluating the treatment effects and prognosis of APL.

Ventricular repolarization dynamics in arsenic trioxide treatment of acute promyelocytic leukemia

BACKGROUND

Arsenic trioxide is the first-line treatment for acute promyelocytic leukemia (APL); however, abnormalities of ventricular repolarization and QT interval prolongation are the most common adverse effects. We explore ventricular repolarization dynamic changes and the influence of clinical factors in APL patients during arsenic trioxide induction therapy.

METHODS

APL patients receiving arsenic trioxide induction therapy were included. Arsenic trioxide effects on ventricular repolarization-related indicators such as QTc, QT interval dispersion (QTd), heart rate-corrected J to T-peak (JTpC), and T-peak to T-end covariate (TpTec) interphase were statistically analyzed. Furthermore, logistic regression analysis was conducted to explore the correlation between various clinical factors and changes in repolarization indexes.

RESULTS

Ninety-three patients were recruited finally. Seven patients with QTc > 500 ms after arsenic trioxide treatment were discontinued from the study. QTc, QTd and JTpC interphase prolonged on day 8; TpTec prolongation was observed at the late induction stage. The risk factors were disease risk, hemoglobin and lactate dehydrogenase for QTc; hemoglobin for QTd; disease risk and hemoglobin for JTpC and TpTec.

CONCLUSION

QTc, QTd and JTpC were prolonged in the early use of arsenic trioxide and in contrast with TpTec. Hypothrombinemia was a common risk factor of ventricular repolarization prolongation and should be considered in preventing cardiac adverse effects of arsenic trioxide in APL patients.

Influence of AS3MT polymorphisms on arsenic metabolism and liver injury in APL patients treated with arsenic trioxide

Arsenic-induced side effects limit its application in the treatment of acute promyelocytic leukemia (APL). We recently demonstrated that AS3MT 14215 (rs3740390) genotypes were associated with urinary arsenic metabolites and hematological and biochemical values. To further decipher the role of AS3MT genotypes on arsenic metabolism and toxicity, AS3MT 27215 (rs11191446), 35587 (rs11191453), 35991 (rs10748835), and their interactive effects were examined in fifty APL patients treated with arsenic trioxide (As₂O₃) for the first time. Urinary arsenic metabolites and methylation capacity indexes were evaluated by the percentage of inorganic arsenic (iAs), monomethylarsonate (MMA), dimethylarsinate (DMA), primary methylation index (PMI, MMA/iAs), secondary methylation index (SMI, DMA/MMA), and total methylation index (TMI, [MMA+DMA]/iAs). Results showed 27215 (rs11191446) genotypes had no statistical significance in arsenic metabolism, as only 5 (10%) patients were the non-wild-type genotypes. 35587 (rs11191453) genotypes were significantly associated with MMA%, DMA%, and SMI. 35991 (rs10748835) genotypes were significantly associated with iAs%, DMA%, PMI, TMI, and the level of ALT and AST. Patients with both 35587 (rs11191453) TT and 35991 (rs10748835) AG+GG genotypes were significantly associated with DMA% and SMI. In addition, patients with both 35991 (rs10748835) AA and 35587 (rs11191453) TC+CC genotypes had the highest DMA%, SMI, and TMI, but the lowest iAs%, ALT and AST level, indicating that additive effects exist on arsenic metabolism and liver function. Our data promotes the realization that AS3MT 35587 (rs11191453), 35991 (rs10748835), especially their joint genotypes 35991 (rs10748835) AA / 35587 (rs11191453) TC+CC, is a novel predictive biomarker for the therapeutic efficacy of As₂O₃ in the treatment of APL.

Arsenic trioxide, a cancer chemo drug hampers fibrotic liver regeneration by interrupting oxidative stress rekindling and stellate cell rejuvenation

After withdrawal of liver toxic insult, the spontaneous regenerative potential of the liver is well reported in the literature. On the other hand, various molecules have been reported to promote as well as delay such natural regeneration. This current study investigates the involvement of arsenic trioxide (ATO) medication at chemotherapeutic dose on the spontaneous regeneration of the CCl₄ induced fibrotic liver. Liver injury markers, such as albumin and SGOT, SGPT, and ALP activities, in serum indicated that ATO supplementation during liver regeneration hampers the rejuvenation process. The hepatic architecture as well as the degree of fibrosis by hematoxylin and eosin and Sirius red staining confirms the above findings. The reduced hepatic antioxidant system and elevated oxidative stress markers, such as lipid peroxidation and 8-hydroxy deoxy-guanosine-positive hepatocytes in ATO supplied rats, display the persistence of oxidative stress when compared with healthy controls and the normal regeneration model. Immuno-histochemical localization of Ki-67 indicates that mitotically active hepatocytes were fewer in the ATO given rats when compared with normal regeneration rats. Further delay in hepatic fibrinolysis was monitored by matrix metalloproteinase zymography assay in the ATO-given animals. Poly(ADP-ribose) polymerase 1 expression demonstrates elevated hepatocyte apoptosis with ATO. Furthermore, increased α-smooth muscle actin indicates that the stellate cells are in an activated state in ATO supplemented fibrotic animals. In conclusion, it's observed that ATO supplementation to the fibrotic liver delays oxidative stress revitalization and maintains stellate cells in the active form, thereby delaying liver regeneration, and the health status of the liver must be taken into account before administering drugs like ATO.