Calcium is a ubiquitous messenger that regulates a wide range of cellular functions, but its involvement in the pathophysiology of acute myeloid leukemia (AML) is not widely investigated. Here, we ...identified, from an analysis of The Cancer Genome Atlas and genotype‐tissue expression databases, stromal interaction molecule 2 (STIM2) as being highly expressed in AML with monocytic differentiation and negatively correlated with overall survival. This was confirmed on a validation cohort of 407 AML patients. We then investigated the role of STIM2 in cell proliferation, differentiation, and survival in two leukemic cell lines with monocytic potential and in normal hematopoietic stem cells. STIM2 expression increased at the RNA and protein levels upon monocyte differentiation. Phenotypically, STIM2 knockdown drastically inhibited cell proliferation and induced genomic stress with DNA double‐strand breaks, as shown by increased levels of phosphorylate histone H2AXγ (p‐H2AXγ), followed by activation of the cellular tumor antigen p53 pathway, decreased expression of cell cycle regulators such as cyclin‐dependent kinase 1 (CDK1)–cyclin B1 and M‐phase inducer phosphatase 3 (CDC25c), and a decreased apoptosis threshold with a low antiapoptotic/proapoptotic protein ratio. Our study reports STIM2 as a new actor regulating genomic stability and p53 response in terms of cell cycle and apoptosis of human normal and malignant monocytic cells.
This research uncovers an important role of STIM2 in the proliferation and survival of normal and malignant monocytic cells. STIM2 knockdown in both cell type leads to decreased cell proliferation and survival through induction of genotoxic stress and induction of p53, leading to cell cycle block and apoptosis in both cell types. STIM2 may be a potential target in AML treatment.
Background: Calcium (Ca2+) is a ubiquitous messenger that regulates a wide range of cellular functions including proliferation, cell migration and apoptosis. Abnormal expression of proteins involved ...in Ca2+ signaling have been associated with oncogenesis in many solid tumor models. However, its involvement in the pathophysiology of acute myeloid leukemia (AML) has been less investigated.Aims: In this work, we aim (i) to identify actors of Ca2+ signaling involved in the pathophysiology of AML, and (ii) to study their function in normal and malignant hematopoiesis.Methods: We first analyzed the TCGA and GTEx databases and identified STIM2 as negatively correlated with overall survival. We investigated using the nCounter® PlexSet™ technology expression of the main Ca2+ regulators in a cohort of 407 patients in the alpha 07-02 protocol with evaluable ELN17 risk. We observed that STIM2 expression was higher in patients with intermediate and unfavorable ELN17 risk (p=.0007) and that increasing STIM2 expression tended to be associated with a lower complete remission when adjusting for ELN17 risk and leukocytosis. Since high STIM2 was associated in databases with AML-M4 and M5, we investigated the role of STIM2 in two leukemic cell lines with monocytic potential, THP1 and OCI-AML3, as well as in in vitro monocytic differentiation of peripheral blood-derived CD34+ cells.Results: In THP1 and OCI-AML3 cells, STIM2 expression increased at RNA and protein level upon monocyte differentiation induced by vitamin D. In CD34+ cells driven in vitro into monocyte differentiation, STIM2 expression increased simultaneously to the acquisition of CD64/CD14 markers. In order to decipher STIM2 function, we used a lentiviral-based shRNA knockdown (KD) strategy. Expression study on 770 genes using the nCounter® PanCancer Pathways Panel in THP1 cells after STIM2 KD identified a transcriptomic signature characterized by a decrease in the expression of genes associated with the MAPK, JAK/STAT, Wnt and Notch pathways, an increased expression of genes regulating the cell cycle and apoptosis. Phenotypically, STIM2 KD inhibited THP1 cell proliferation, induced a cell cycle blockage in G2/M and a massive apoptosis. Moreover, STIM2 KD significantly inhibited monocytic differentiation in the presence of Vitamin D. In primary cells, STIM2 KD induced a similar phenotype, including inducing apoptosis and blockage in G2/M. In THP1 and primary cells, STIM2 KD was associated with decreased level of p-Rb, Bcl2, Bcl-XL and MCL-1, increased level of the pro apoptotic Bad and Bax, and cleavage of caspase 9 without cleavage of caspase 8, revealing activation of mitochondrial apoptosis. Assessing cell cycle regulators, we observed a decreased expression of Cyclin B1, CDK1 and the phosphatase cdc25c, involved during the G2/M transition. We hypothesized that dysregulation in Ca2+ level mediated by STIM2 KD induced a genotoxic stress, leading to DNA double stranded breaks and p53 induction. Using Western Blot, we observed that STIM2KD increased p53, and induced pH2AX foci. Chemical inhibition of p53 using pifithrin-α partially reverted the apoptotic death, as well as the G2/M blockage induced by STIM2KD in both THP1 and in primary cells after STIM2 KD.Summary/Conclusion: Our data evoke a negative prognostic role of STIM2 in AML. We highlight a role of STIM2 in cell proliferation and survival via protection against genotoxic stress and p53-dependent control of apoptosis and cell cycle in leukemic and myeloid cells. STIM2 acts as a Ca2+ censor, detecting reticular calcium depletion and opening of ORAI channels at cell membrane. Studies are underway to determine whether the role of STIM2 described here involve a modification of calcium fluxes via this capacitive entry of Ca2+ from the extracellular medium.
Cat-eye syndrome is a rare genetic syndrome of chromosomal origin. Individuals with cat-eye syndrome are characterized by the presence of preauricular pits and/or tags, anal atresia, and iris ...coloboma. Many reported cases also presented with variable congenital anomalies and intellectual disability. Most patients diagnosed with CES carry a small supernumerary bisatellited marker chromosome, resulting in partial tetrasomy of 22p-22q11.21. There are two types of small supernumerary marker chromosome, depending on the breakpoint site. In a very small proportion of cases, other cytogenetic anomalies are reportedly associated with the cat-eye syndrome phenotype. Here, we report a patient with cat-eye syndrome caused by a type 1 small supernumerary marker chromosome. The phenotype was atypical and included a severe developmental delay. The use of array comparative genomic hybridization ruled out the involvement of another chromosomal imbalance in the neurological phenotype. In the literature, only a few patients with cat-eye syndrome present with a severe developmental delay, and all of the latter carried an atypical partial trisomy 22 or an uncharacterized small supernumerary marker chromosome. Hence, this is the first report of a severe neurological phenotype in cat-eye syndrome with a typical type 1 small supernumerary marker chromosome. Our observation clearly complicates prognostic assessment, particularly when cat-eye syndrome is diagnosed prenatally.
•We report a detailed case of type 2 Timothy syndrome due to a p.(Gly402Ser) mutation in exon 8 of the CACNA1C gene.•Adding Mexiletine to Nadolol resulted in a reduction of the QTc and a slight ...decrease in the number of appropriate shocks during a long-term follow up of nine years.•Left cardiac sympathetic denervation also appears to have been effective.
We report a detailed case of type 2 TS due to a p.(Gly402Ser) mutation in exon 8 of the CACNA1C gene. The patient shows a marked prolongation of repolarization with a mean QTc of 540 ms. He shows no structural heart disease, syndactyly, or cranio-facial abnormalities. However, he shows developmental delays, without autism, and dental abnormalities. The cardiac phenotype is very severe, with a resuscitated cardiac arrest at 2.5 years of age, followed by 26 appropriate shocks during nine years of follow-up. Adding mexiletine to nadolol resulted in a reduction of the QTc and a slight decrease in the number of appropriate shocks.
•Empty follicle syndrome is failure to retrieve oocytes after ovarian stimulation.•Genuine EFS is caused by mutations in genes encoding zona pellucida (ZP) proteins.•We report on genuine EFS caused ...by a ZP1 mutation.•Genuine EFS should prompt the sequencing of genes encoding ZP proteins.
Genuine empty follicle syndrome (gEFS) is a rare cause of female infertility; it is defined as the presence of cumulus-oocyte complexes (COCs) in follicular fluid but the absence of oocytes after denudation in an in vitro fertilization (IVF) programme. Mutations in one of the four genes encoding zona pellucida (ZP) proteins have been implicated in gEFS.
The objectives of the present study were to explore the molecular basis of idiopathic infertility in a 35-year-old woman with gEFS (observed after four ovarian retrievals), compare her phenotype and genotype with those of other patients described in the literature, and discuss therapeutic approaches that could be adopted by reproductive health centres in this situation.
Sequencing of the ZP genes revealed a new homozygous missense variant in ZP1: c.1097G > A;p.(Arg366Gln). The variant is located in the ZP-N domain, which is essential for ZP protein polymerization. An immunohistochemical assessment of an ovarian biopsy confirmed the absence of ZP1 protein. The novel variant appears to prevent ZP assembly, which would explain the absence of normal oocytes after denudation in our patient (and despite the retrieval of COCs).
ZP gene sequencing should be considered for patients with a phenotype suggestive of gEFS. An etiological genetic diagnosis enables appropriate genetic counselling and a switch to an IVF programme (with a suitable denudation technique) or an oocyte donation programme.
Acute lymphoblastic leukemias (ALL) are characterized by a large number of cytogenetic abnormalities of clinical interest that require the use of several complementary techniques. Optical genome ...mapping (OGM) is based on analysis of ultra‐high molecular weight DNA molecules that provides a high‐resolution genome‐wide analysis highlighting copy number and structural anomalies, including balanced translocations. We compared OGM to standard techniques (karyotyping, fluorescent in situ hybridization, single nucleotide polymorphism‐array and reverse transcription multiplex ligation‐dependent probe amplification) in 10 selected B or T‐ALL. Eighty abnormalities were found using standard techniques of which 72 (90%) were correctly detected using OGM. Eight discrepancies were identified, while 12 additional anomalies were found by OGM. Among the discrepancies, four were detected in raw data but not retained because of filtering issues. However, four were truly missed, either because of a low variant allele frequency or because of a low coverage of some regions. Of the additional anomalies revealed by OGM, seven were confirmed by another technique, some of which are recurrent in ALL such as LMO2‐TRA and MYC‐TRB fusions. Despite false positive anomalies due to background noise and a case of inter‐sample contamination secondarily identified, the OGM technology was relatively simple to use with little practice. Thus, OGM represents a promising alternative to cytogenetic techniques currently performed for ALL characterization. It enables a time and cost effective analysis allowing identification of complex cytogenetic events, including those currently inaccessible to standard techniques.
Chorionic villus sampling (CVS) allows for earlier results for aneuploidy or genomic abnormalities compared to amniocentesis. Nevertheless, the inability to provide complete results has been ...described as being more frequent with CVS. This study was conducted in order to identify risk factors for such failures.
A retrospective single-center study was performed from January 2014 to December 2018. Participants were divided into two groups depending on whether complete CVS results were issued ("successful CVS group") or not ("failed CVS group"). Failure affected preliminary short-term cultures, long-term cultures, or both.
During the study period, 214 CVS were performed, 73 (34%) of which were classified in the failed CVS group. We observed significant intergroup differences between the successful and failed CVS groups for four variables: BMI (respectively 23.9 ±5.88 and 25.9 ±6.13 kg/m
2
), term at sampling (12.9 ±1.35 and 12.6 ±1.09 weeks gestation), trophoblastic location (posterior in 49 40% and 37 66% cases), and sampling approach (transcervical in 54 43% and 36 64% cases) (p < .05). In a stepwise binary logistic regression analysis, higher BMI, posterior trophoblastic location, and transcervical sampling approach were the only variables negatively influencing CVS success, with respective aOR 95% CI of 0.947 0.898; 0.996, 0.322 0.160; 0.634, and 0.466 0.238; 0.900.
In the presence of CVS failure risk factors, a discussion could be initiated regarding a deferred amniocentesis as a first option.
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