A Rare Heterozygous TINF2 Deletional Frameshift Mutation in a Chinese Pedigree With a Spectrum of TBDs Phenotypes.

Telomere biology disorders (TBDs) induced by TINF2 mutations manifest clinically with a spectrum of phenotypes, from silent carriers to a set of overlapping conditions. A rare TINF2 frameshift mutation (c.591delG) encoding a truncated mutant TIN2 protein (p.W198fs) was identified in a 6-years-and-3-month-old Chinese girl with neuroblastoma (NB) by next generation sequencing and confirmed by Sanger sequencing. To explore the possible implications of TINF2 mutations in TBDs development, the TINF2 mutant was transfected into the human embryonic kidney (HEK) 293T cells, and mRNA expression of the shelterin complex components as well as the cellular distribution of mutant TIN2 were examined. The TINF2 mutation was phenotypically associated with short stature in the proband, nail dystrophy and spotted hypopigmentation in her mother, and psoriasis in her older brother. I-TASSER modeling analysis revealed conformational changes of the mutant TIN2 protein and loss of pivotal domains downstream of the 198th amino acid. Additionally, mRNA expression of the shelterin components was downregulated, and TIN2 mutant protein expression was reduced in HEK293T cells transfected with mutant TINF2. Furthermore, instead of being restricted to the nucleus, the mutant TIN2 was identified in both the cytoplasm and the nucleus. The TINF2 gene mutation might impair the function of the shelterin complex and the telomere maintenance mechanisms, both of which are involved in the development of TBDs. TBDs have been associated with increased cancer risk. To the best of our knowledge, this is the first report of NB in patients with TBDs. The relationship between the TINF2 mutation and NB may need to further study.

A Marine Alkaloid, Ascomylactam A, Suppresses Lung Tumorigenesis via Inducing Cell Cycle G1/S Arrest through ROS/Akt/Rb Pathway.

Ascomylactam A was reported for the first time as a new 13-membered-ring macrocyclic alkaloid in 2019 from the mangrove endophytic fungus Didymella sp. CYSK-4 from the South China Sea. The aim of our study was to delineate the effects of ascomylactam A (AsA) on lung cancer cells and explore the antitumor molecular mechanisms underlying of AsA. In vitro, AsA markedly inhibited the cell proliferation with half-maximal inhibitory concentration (IC50) values from 4 to 8 µM on six lung cancer cell lines, respectively. In vivo, AsA suppressed the tumor growth of A549, NCI-H460 and NCI-H1975 xenografts significantly in mice. Furthermore, by analyses of the soft agar colony formation, 5-ethynyl-20-deoxyuridine (EdU) assay, reactive oxygen species (ROS) imaging, flow cytometry and Western blotting, AsA demonstrated the ability to induce cell cycle arrest in G1 and G1/S phases by increasing ROS generation and decreasing of Akt activity. Conversely, ROS inhibitors and overexpression of Akt could decrease cell growth inhibition and cell cycle arrest induced by AsA. Therefore, we believe that AsA blocks the cell cycle via an ROS-dependent Akt/Cyclin D1/Rb signaling pathway, which consequently leads to the observed antitumor effect both in vitro and in vivo. Our results suggest a novel leading compound for antitumor drug development.

C1orf194 deficiency leads to incomplete early embryonic lethality and dominant intermediate Charcot-Marie-Tooth disease in a knockout mouse model.

Charcot-Marie-Tooth (CMT) disease is the most common inherited peripheral neuropathy and shows clinical and genetic heterogeneity. Mutations in C1orf194 encoding a Ca2+ regulator in neurons and Schwann cells have been reported previously by us to cause CMT disease. In here, we further investigated the function and pathogenic mechanism of C1or194 by generating C1orf194 knockout (KO) mice. Homozygous mutants of C1orf194 mice exhibited incomplete embryonic lethality, characterized by differentiation abnormalities and stillbirth on embryonic days 7.5-15.5. Heterozygous and surviving homozygous C1orf194 KO mice developed motor and sensory defects at the age of 4 months. Electrophysiologic recordings showed decreased compound muscle action potential and motor nerve conduction velocity in the sciatic nerve of C1orf194-deficient mice as a pathologic feature of dominant intermediate-type CMT. Transmission electron microscopy analysis revealed demyelination and axonal atrophy in the sciatic nerve as well as swelling and loss of mitochondrial matrix and other abnormalities in axons and Schwann cells. A histopathologic examination showed a loss of motor neurons in the anterior horn of the spinal cord and muscle atrophy. Shorter internodal length between nodes of Ranvier and Schmidt-Lanterman incisures was detected in the sciatic nerve of affected animals. These results indicate that C1orf194 KO mice can serve as an animal model of CMT with a severe dominant intermediate CMT phenotype that can be used to investigate the molecular mechanisms of the disease and evaluate the efficacy of therapeutic strategies.

[Clinical and Cytogenetic Characteristics of Two AML Patients with High-level MLL Expression].

OBJECTIVE: To investigate the clinical and cytogenetic characteristics of high-level mixed-lineage leukaemia (MLL) gene amplification in patients with acute myeloid leukemia (AML). METHODS: The clinical and cytogenetic data of 2 AML patients with high-level MLL amplification from January 2010 to August 2016 were analyzed retrospectively. RESULTS: The two AML cases were in middle-aged population. They were diagnosed as FAB subtype M5b and M2a respectively. Both of them had complex karyotypes with the aberrations of chromosome 11. One case was confirmed as MLL-PTD involving exons 2-9 by RT-PCR and sequencing. The other case without MLL-PTD was further analyzed by CytoScan HD analysis. The CMA results showed partial gain of 11q accompanied with partial loss in 11q, deletion of regions in 3p, 3q, 4q, 5q, 7q, 8q, 10p, 10q, 12p and 18q, as well as gain of 4p. CONCLUSION: The co-existence of -5/5q-, -7/7q- and highly complex karyotype may accelerate the poor prognosis. Thus how those cytogenetic abnormalities influencing the disease prognosis need to be further explored.

[Application of Combined Detection of Fusion Gene and BIOMED-2 Standardized Ig Gene Rearrangement System in Childhood B-cell Acute Lymphoblastic Leukemia].

OBJECTIVE: To explore the application of combined detection of fusion gene and BIOMED-2 standardized immunoglobulin (Ig) gene rearrangement system in diagnosis and treatment of children with acute lymphoblastic leukemia (ALL). METHODS: Multiplex-PCR amplifications and RQ-PCR of RNA/DNA were performed using ALL fusion gene detection kit and BIOMED-2 primer. The Ig gene rearrangements were analyzed by using PCR fragment analysis system. RESULTS: Out of 251 children with B-ALL, 77 cases were TEL-AML1(+) , 28 cases were E2A-PBX1(+) , 10 cases were MLL-AF4(+) , 11 cases were BCR-ABL(+) , the total positive rate was 50.2%, 82.5% showed IgH VH-JH rearrangement, 53.4% showed IgK rearrangement. The positive rate of combined detection of fusion gene and gene rearrangement was 99%. E2A-PBX1(+) and MLL-AF4(+) with IgK(+) gene rearrangement group was compared with negative control group, the difference was statistically significant (P < 0.001 or P = 0.005); 105 ALL fusion gene positive cases had been detected by fluorescence in situ hybridization (FISH) simultaneously, the accordance rate of fusion gene and FISH was more than 94%. CONCLUSION: The combined detection of ALL fusion gene and BIOMED-2 standardized clonality analysis system can improve the positive detected rate of B-ALL dramatically, and make the grouping of disease prognosis more accurately; this combined detection is a more faster and sensitive method than FISH.

Enlarged and prominent nucleus may be indicative of tetraploidy: a laboratory study of a rare near-tetraploidy in a child patient with acute myelogenous leukemia AML-M4.

SUMMARY: Near-tetraploidy is a rare cytogenetic abnormality in myelocytic malignancies in children and its significance is unknown. To investigate the pathologic characteristics of a near-tetraploidy in a child with acute myelogenous leukemia (AML-M4), bone marrow smears were prepared for morphologic analysis. Bone marrow samples were collected at presentation for flow cytometry, prepared by short-term (24 h) unstimulated culture and R-banding for conventional cytogenetic assay. We have performed a multifactorial analysis of the laboratory test results. In this case, the chromosomal analysis (R-banding) demonstrated a near-tetraploidy. Combined with morphologic and immunophenotypic results, the diagnosis was established as acute myelogenous leukemia (AML-M4). Near-tetraploidy is an uncommon cytogenetic finding, and the experience of this case further emphasizes the importance of the laboratory diagnostic methods.

[Immunophenotypes, cytogenetics and clinical features of 192 patients with acute myeloid leukemia].

The objective of this study was to investigate the immunophenotypic subtype profiles of 192 patients with acute myeloid leukemia (AML) and its association to cytogenetics and clinical features. Immunophenotyping of 192 patients was performed by flow cytometry using a panel of monoclonal antibodies. The karyotypes in 125 out of 192 cases were analyzed by G-banding technology. The results showed that CD33, CD13, myeloperoxidase (MPO) and CD117 were the most commonly expressed antigens in AML. CD117 expressed in 84.6% of AML-M3 cases. A combination of intensive autofluorescence, both CD34- and HLA-DR-, and high expression of CD13, CD33 and MPO had significant value for AML-M3 diagnosis. CD14 expressed only in AML-M4 and AML-M5, and both intensive positivity of CD64 and CD15 with high expression of HLA-DR may suggest great possibility for diagnosis of AML-M5. Lymphoid marker expression was documented in 47.9% of the 192 AML cases. CD56 (26.0%) and CD7 (20.8%) were the most commonly expressed lymphoid markers in AML patients, followed by CD19 (9.9%) and CD2 (7.3%). Abnormal karyotypes were detected in 76 out of 125 cases (60.8%). Correlation test showed that t(8;21) was found only in 17 cases of AML-M2 and strongly associated with the individual or combinational expressions of CD15/CD19/CD56. And 28 cases of t(15;17) were found in AML-M3; 2 cases of inv(16) were found in AML-M4EO. Higher CD34 positivity was found in LymAg+ group (77.2%) than that in LymAg- group (48.0%). It is concluded that immunophenotype analysis is useful for AML diagnosis and classification, and the immunophenotype has close relevance to the abnormal cytogenetic changes and clinical features in AML. The results suggested that a new prognostic scoring system that integrated the morphology, cytogenetic abnormalities and immunophenotype parameters would benefit the diagnosis, classification, and estimation of prognosis in AML patients.

Laboratory study on near-tetraploid acute myelogenous leukemia of childhood.

Near-tetraploidy is a rare cytogenetic abnormality in myelocytic malignancies in children, and its significance is unknown. To investigate the characteristics of near-tetraploidy in a child with acute myelogenous leukemia (AML-M4), bone marrow smears were prepared for morphological analysis. Bone marrow samples were collected for flow cytometry, and prepared by short-term (24 hrs) unstimulated culture and R-banding for conventional cytogenetic assay. In this case, the morphological analysis of bone marrow cells showed large and prominent nuclei. The chromosomal analysis (R-banding) demonstrated a near-tetraploidy. Combined with morphological and immunophenotypic results, AML-M4 was confirmed. The patient was given four cycles of chemotherapy, and finally achieved clinical remission. However, the duration achieving the remission in the child was longer than AML children with normal karyotype. It is believed that near-tetraploid karyotype may have a great significance to the therapy and prognosis.