Molecular background and therapeutic perspectives of acute lymphoblastic leukemia BCR-ABL1-like

Białaczka BCR-ABL1-like jest nowo wyodrębnionym podtypem ostrej białaczki limfoblastycznej (ALL) wysokiego ryzyka, wywodzącym się z komórek prekursorowych limfocytów B (BCP-ALL), który charakteryzuje profil ekspresji genów podobny do białaczki Philadelphia-pozytywnej mimo braku fuzji genów BCR-ABL1. Częstość występowania na poziomie 15% oraz wysokie ryzyko wznowy i zgonu w przypadkach BCR-ABL1-like skłania do eksplorowania podłoża molekularnego tego nowotworu oraz opracowywania nowych strategii terapeutycznych. Około 80% zaburzeń genetycznych obserwowanych w BCR-ABL1-like ALL dotyczy genów zaangażowanych w różnicowaniei dojrzewanie linii B (IKZF1, PAX5, E2A, EBF1 i VPREB1), a także regulujących procesy proliferacjilimfocytów B (CRLF2, CDKN2A/2B). Specyficzne dla tego podtypu białaczki są też fuzje genów PDGFRB, ABL1, JAK prowadzące do aktywacji kinaz szlaków metabolicznych promujących nowotworzenie. Wiele spośród zidentyfikowanych, nadaktywnych ścieżek sygnałowych może być hamowanych za pomocą dostępnych leków ukierunkowanych molekularnie.BCR-ABL1-like acute lymphoblastic leukemia (ALL) is newly identified subtype of high-risk B-cell progenitor acute lymphoblastic leukemia (BCP-ALL), which exhibit gene expression signature similar to that of BCR-ABL1–positive leukemia, but without characteristic BCR-ABL1 gene fusion. Since the frequency of the BCR-ABL1-like ALL is relatively high (15%) and the risk of relapse issignificantly increased, molecular pathogenesis of this subtype is widely explored. Approximately 80% of genetic lesions in the BCR-ABL1-like ALL refer to genes involved in B-cell differentiation and maturation (IKZF1, PAX5, E2A, EBF1 and VPREB1) as well as to genes that regulateB-lymphocyte proliferation (CRLF2, CDKN2A/2B). Moreover, BCR-ABL1-like ALL is also characterized by gene fusions involving PDGFRB, ABL1, JAK genes which activate kinases of specific,metabolic pathways responsible for cancer development. Many of identified up-regulated signaling pathways can be inhibited by currently clinically available molecular targeted drugs

Dyskeratosis congenita as a multifaceted bone marrow disorder

Dyskeratosis congenita (DC) is a rare multisystem clinical entity caused by genetic mutations associated with telomere biology disorder. The symptoms include bone marrow dysfunction as well as skin and mucosal abnormalities. In severe cases, DC is characterized by high mortality rates among children. In milder subtypes, it is less detectable in adults, due to the occurrence of cryptic forms of the disease. To date, more than 15 mutated genes have been shown as causative for DC. The aim of this study was to provide a brief description of the currently known clinical and genetic characteristics of DC, and to elucidate the molecular pathogenesis

Differential regulation of serum microRNA expression by HNF1β and HNF1α transcription factors.

We aimed to identify microRNAs (miRNAs) under transcriptional control of the HNF1β transcription factor, and investigate whether its effect manifests in serum.This article is freely available via Open Access. Click on the 'Additional Link' above to access the full-text via the publisher's site.Published (Open Access

The kinetics of blast clearance are associated with copy number alterations in childhood B-cell acute lymphoblastic leukemia

We analyzed the pattern of whole-genome copy number alterations (CNAs) and their association with the kinetics of blast clearance during the induction treatment among 195 pediatric patients with B-cell precursor acute lymphoblastic leukemia (BCP-ALL) who displayed intermediate or high levels of minimal residual disease (MRD). Using unsupervised hierarchical clustering of CNAs > 5 Mbp, we dissected three clusters of leukemic samples with distinct kinetics of blast clearance [A – early slow responders (n=105), B – patients with persistent leukemia (n=24), C – fast responders with the low but detectable disease at the end of induction (n=66)] that corresponded with the patients’ clinical features, the microdeletion profile,the presence of gene fusions and patients survival. Low incidence of large CNAs and chromosomal numerical aberrations occurred in cluster A which included ALL samples showing recurrent microdeletions within the genes encoding transcription factors (i.e., IKZF1, PAX5, ETV6, and ERG), DNA repair genes (XRCC3 and TOX), or harboring chromothriptic pattern of CNAs. Low hyperdiploid karyotype with trisomy 8 or hypodiploidy was predominantly observed in cluster B. Whereas cluster C included almost exclusively high-hyperdiploid ALL samples with concomitant mutations in RAS pathway genes. The pattern of CNAs influences the kinetics of leukemic cell clearance and selected aberrations affecting DNA repair genes may contribute to BCP-ALL chemoresistance

Biallelic loss of CDKN2A is associated with poor response to treatment in pediatric acute lymphoblastic leukemia

The inactivation of tumor suppressor genes located within 9p21 locus (CDKN2A, CDKN2B) occurs in up to 30% of children with B-cell precursor acute lymphoblastic leukemia (BCP-ALL), but its independent prognostic significance remains controversial. In order to investigate the prognostic impact of deletions and promoter methylation within 9p21, 641 children with newly diagnosed BCP-ALL using methylation specific multiplex ligation-dependent probe amplification (MS-MLPA) were investigated. A total of 169 (26.4%) microdeletions in 9p21 were detected, of which 71 were homozygous. Patients with CDKN2A homozygous deletions were older at diagnosis (p < .001), more frequently steroid resistant (p = .049), had higher WBC count (p < .001), higher MRD at Day 15 (p = .013) and lower relapse-free survival [p = .028, hazard ratio: 2.28 (95% confidence interval: 1.09-4.76)] than patients without these alterations. CDKN2A homozygous deletions coexisted with IKZF1 and PAX5 deletions (p < .001). In conclusion, CDKN2A homozygous deletions, but not promoter methylation, are associated with poor response to treatment and increased relapse risk of pediatric BCP-ALL.status: publishe

Elevated level of lysophosphatidic acid among patients with HNF1B mutations and its role in RCAD syndrome : a multiomic study

INTRODUCTION: Patients with hepatocyte nuclear factor-1 beta (HNF1B) mutations present a variable phenotype with two main symptoms: maturity onset diabetes of the young (MODY) and polycystic kidney disease (PKD). OBJECTIVES: Identification of serum metabolites specific for HNF1Bmut and evaluation of their role in disease pathogenesis. METHODS: We recruited patients with HNF1Bmut (N = 10), HNF1Amut (N = 10), PKD: non-dialyzed and dialyzed (N = 8 and N = 13); and healthy controls (N = 12). Serum fingerprinting was performed by LC-QTOF-MS. Selected metabolite was validated by ELISA (enzyme-linked immunosorbent assay) measurements and then biologically connected with HNF1B by in silico analysis. HepG2 were stimulated with lysophosphatidic acid (LPA) and HNF1B gene was knocked down (kd) by small interfering RNA. Transcriptomic analysis with microarrays and western blot measurements were performed. RESULTS: Serum levels of six metabolites including: arachidonic acid, hydroxyeicosatetraenoic acid, linoleamide and three LPA (18:1, 18:2 and 20:4), had AUC (the area under the curve) > 0.9 (HNF1Bmut vs comparative groups). The increased level of LPA was confirmed by ELISA measurements. In HepG2(HNF1Bkd) cells LPA stimulation lead to downregulation of many pathways associated with cell cycle, lipid metabolism, and upregulation of steroid hormone metabolism and Wnt signaling. Also, increased intracellular protein level of autotaxin was detected in the cells. GSK-3alpha/beta protein level and its phosphorylated ratio were differentially affected by LPA stimulation in HNF1Bkd and control cells. CONCLUSIONS: LPA is elevated in sera of patients with HNF1Bmut. LPA contributes to the pathogenesis of HNF1B-MODY by affecting Wnt/GSK-3 signaling. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11306-022-01873-z

Targeting the thioredoxin system as a novel strategy against B cell acute lymphoblastic leukemia.

B cell precursor acute lymphoblastic leukemia (BCP-ALL) is a genetically heterogeneous blood cancer characterized by abnormal expansion of immature B cells. Although intensive chemotherapy provides high cure rates in a majority of patients, subtypes harboring certain genetic lesions, such as MLL rearrangements or BCR-ABL1 fusion, remain clinically challenging, necessitating a search for other therapeutic approaches. Herein, we aimed to validate antioxidant enzymes of the thioredoxin system as potential therapeutic targets in BCP-ALL. We observed oxidative stress along with aberrant expression of the enzymes associated with the activity of thioredoxin antioxidant system in BCP-ALL cells. Moreover, we found that auranofin and adenanthin, inhibitors of the thioredoxin system antioxidant enzymes, effectively kill BCP-ALL cell lines and pediatric and adult BCP-ALL primary cells, including primary cells co-cultured with bone marrow-derived stem cells. Furthermore, auranofin delayed the progression of leukemia in MLL-rearranged patient-derived xenograft model and prolonged the survival of leukemic NSG mice. Our results unveil the thioredoxin system as a novel target for BCP-ALL therapy, and indicate that further studies assessing the anticancer efficacy of combinations of thioredoxin system inhibitors with conventional anti BCP-ALL drugs should be continued