Clinical impact ofin vitrocellular drug resistance on childhood acute lymphoblastic leukemia in Taiwan

Pharmacotypes across the genomic landscape of pediatric acute lymphoblastic leukemia and impact on treatment response

Contemporary chemotherapy for childhood acute lymphoblastic leukemia (ALL) is risk-adapted based on clinical features, leukemia genomics and minimal residual disease (MRD); however, the pharmacological basis of these prognostic variables remains unclear. Analyzing samples from 805 children with newly diagnosed ALL from three consecutive clinical trials, we determined the ex vivo sensitivity of primary leukemia cells to 18 therapeutic agents across 23 molecular subtypes defined by leukemia genomics. There was wide variability in drug response, with favorable ALL subtypes exhibiting the greatest sensitivity to L-asparaginase and glucocorticoids. Leukemia sensitivity to these two agents was highly associated with MRD although with distinct patterns and only in B cell ALL. We identified six patient clusters based on ALL pharmacotypes, which were associated with event-free survival, even after adjusting for MRD. Pharmacotyping identified a T cell ALL subset with a poor prognosis that was sensitive to targeted agents, pointing to alternative therapeutic strategies. Our study comprehensively described the pharmacological heterogeneity of ALL, highlighting opportunities for further individualizing therapy for this most common childhood cancer.

Role and Mechanism of lncRNA-pvt1 in the Pathogenesis of Acute Lymphoblastic Leukemia in Children

Objective

To investigate the role and mechanism of lncRNA-pvt1 in the pathogenesis of childhood acute lymphoblastic leukemia (ALL).

Methods

The expression of lncRNA-pvt1 in bone marrow tissues of ALL patients after initial diagnosis and complete remission was detected by RT-PCR to explore its possible involvement in the pathogenesis of ALL. The proliferation and apoptosis of Jurkat cells transfected with lncRNA-pvt1 were observed by MTT and flow cytometry.

Results

lncRNA-pvt1 expression was upregulated in bone marrow of ALL patients. Knockdown of lncRNA-pvt1 inhibited Jurkat cell proliferation and increased its apoptosis rate.

Conclusion

Silencing lncRNA-pvt1 expression can inhibit the development of ALL.

N1-guanyl-1,7-diaminoheptane enhances the chemosensitivity of acute lymphoblastic leukemia cells to vincristine through inhibition of eif5a-2 activation

N1-guanyl-1,7-diaminoheptane (GC7), a deoxyhypusine synthase inhibitor, has been shown to exert antiproliferation effects in many solid tumors by regulating eukaryotic translation initiation factor 5a2 (eif5a-2). However, little is known about the role of GC7 and eif5a-2 in drug resistance in acute lymphoblastic leukemia (ALL). In the present study, we investigated the effect of GC7 on drug-resistant ALL and its potential mechanism. We found that using the CCK-8 assay that combined treatment with GC7 and vincristine (VCR) significantly inhibited the cell viability of two ALL cell lines. Using EdU incorporation assays and flow cytometry, we also showed that GC7 could markedly enhance the VCR sensitivity of ALL cells by suppressing cell proliferation and promoting apoptosis. Furthermore, we showed that GC7 could downregulate eif5a-2 and myeloid cell leukemia-1 (Mcl-1) expression. Knockdown of eif5a-2 inhibited the expression of Mcl-1 and significantly enhanced the VCR sensitivity. Moreover, eif5a-2 knockdown decreased the regulatory role of GC7 in increasing VCR sensitivity. Thus, our findings indicate that combined treatment with GC7 could enhance VCR sensitivity of ALL cells by regulating the eif5a-2/Mcl-1 axis. Together, our results highlight the potential clinical application of GC7 in VCR-based chemotherapy for the treatment of ALL.

Multidrug resistance gene 1 polymorphisms in pediatric patients with leukemia at a national referral hospital in Indonesia

Background

Acute lymphoblastic leukemia (ALL) is the most prevalent cancer in the pediatric population. From 25% to 30% of patients with ALL will have a relapse that leads to death when they are teenagers. At Cipto Mangunkusumo Hospital, 40% of 126 pediatric patients with ALL relapsed from 2005 to 2011. A multiple variant of multidrug resistance gene 1 (MDR1) is C3435T, which can be used to understand the genetic basis of susceptibility to relapse.

Objectives

To identify the profile of MDR1 polymorphism in pediatric Indonesian patients with ALL.

Methods

We collected data from 44 patients with ALL who attended Cipto Mangunkusumo Hospital between January and June 2014. We investigated a silent C3435T polymorphism in MDR1 exon 26 with polymerase chain reaction- restriction fragment length polymorphism using MboI.

Results

There were 32 male and 12 female patient participants in this study. Eighteen patients were 1–3 years old and 26 were over 3 years. The mean age at 1–3 years was 2.4 ± 0.86, and over 3 years it was 6.3 ± 2.67 years. There were 27 patients with ALL in the standard risk group and 17 in the high risk group. We determined that the 25 samples from patients with ALL in the standard risk group were not digestible (allele T) and the 6 samples from patients with ALL in the high risk group were digestible (allele C).

Conclusions

The prevalence of the T allele was higher than that of the C allele in pediatric Indonesian patients with ALL.

Asparaginase Therapy in Pediatric Acute Lymphoblastic Leukemia: A Focus on the Mode of Drug Resistance

Asparaginase is one of the most important chemotherapeutic agents against pediatric acute lymphoblastic leukemia (ALL), the most common form of childhood cancer. The therapeutic efficacy (e.g., chemoresistance) and adverse effects of asparaginase (e.g., hypersensivity and pancreatitis) have been investigated over the past four decades. It was suggested early on that leukemic cells are resistant to asparaginase because of their increased asparagine synthetase activity. Afterward, other mechanisms associated with asparaginase resistance were reported. Not only leukemic cells but also patients themselves may play a role in causing asparaginase resistance, which has been associated with unfavorable outcome in children with ALL. This article will briefly review asparaginase therapy in children with ALL and comprehensively analyze recent reports on the potential mechanisms of asparaginase resistance.

Incidence, risk factors, and treatment outcome of symptomatic osteonecrosis in Taiwanese children with acute lymphoblastic leukemia: a retrospective cohort study of 245 patients in a single institution

Osteonecrosis (ON) is a potentially disabling complication encountered in children who receive chemotherapy for acute lymphoblastic leukemia (ALL). Considering the possible effect of ethnic difference on the clinical features of symptomatic ON in pediatric ALL, we retrospectively evaluated 245 children with ALL who were treated at Chang Gung Memorial Hospital, Linkou, between 2002 and 2011. Six (2.4 %) patients developed symptomatic ON in a total of 17 sites during the follow-up period. Diagnosis of ON was confirmed by X-ray in seven, magnetic resonance imaging in two, and bone scan in three patients. The estimated cumulative incidence of symptomatic ON in newly diagnosed ALL was 3.4 % at 8 years. Four patients received ON-directed surgical interventions, including total hip replacement in three and arthroplasty in one. The incidence of ON was significantly higher among girls (P = 0.03), patients >10 years old (P = 2.2 × 10(-4)), and patients who had received more intensive chemotherapy regimen (P = 0.02). These results indicate that the incidence and risk factors in our institute were similar to those observed in Western countries. Future studies surveying the impact on the quality of life of childhood ALL survivors in Taiwan are warranted.