Tisagenlecleucel is a CD19 chimeric antigen receptor (CAR) T-cell therapy approved for treatment of pediatric and young adult patients with relapsed/refractory acute lymphoblastic leukemia (ALL) and adults with non-Hodgkin lymphoma (NHL). The initial experience with tisagenlecleucel in a real-world setting from a cellular therapy registry is presented here. As of January 2020, 511 patients were enrolled from 73 centers, and 410 patients had follow-up data reported (ALL, n = 255; NHL, n = 155), with a median follow-up of 13.4 and 11.9 months for ALL and NHL, respectively. Among patients with ALL, the initial complete remission (CR) rate was 85.5%. Twelve-month duration of response (DOR), event-free survival, and overall survival (OS) rates were 60.9%, 52.4%, and 77.2%, respectively. Among adults with NHL, the best overall response rate was 61.8%, including an initial CR rate of 39.5%. Six-month DOR, progression-free survival, and OS rates were 55.3%, 38.7%, and 70.7%, respectively. Grade ≥3 cytokine release syndrome and neurotoxicity were reported in 11.6% and 7.5% of all patients, respectively. Similar outcomes were observed in patients with in-specification and out-of-specification products as a result of viability <80% (range, 61% to 79%). This first report of tisagenlecleucel in the real-world setting demonstrates outcomes with similar efficacy and improved safety compared with those seen in the pivotal trials.

SUMMARYMicrocephaly affects ~1% of the population and is associated with mental retardation, motor defects and, in some cases, seizures. We analyzed the mechanisms underlying brain size determination in a mouse model of human microcephaly. The Hertwig's anemia (an) mutant shows peripheral blood cytopenias, spontaneous aneuploidy and a predisposition to hematopoietic tumors. We found that the an mutation is a genomic inversion of exon 4 of Cdk5rap2, resulting in an in-frame deletion of exon 4 from the mRNA. The finding that CDK5RAP2 human mutations cause microcephaly prompted further analysis of Cdk5rap2 an/an mice and we demonstrated that these mice exhibit microcephaly comparable to that of the human disease, resulting from striking neurogenic defects that include proliferative and survival defects in neuronal progenitors. Cdk5rap2 an/an neuronal precursors exit the cell cycle prematurely and many undergo apoptosis. These defects are associated with impaired mitotic progression coupled with abnormal mitotic spindle pole number and mitotic orientation. Our findings suggest that the reduction in brain size observed in humans with mutations in CDK5RAP2 is associated with impaired centrosomal function and with changes in mitotic spindle orientation during progenitor proliferation.

This article reports the outcomes of a clinical trial of CD28-containing CD19-specific chimeric antigen receptor (CAR) T cells in pediatric, adolescent, and young adult patients with relapsed or refractory B-cell acute lymphoblastic leukemia (B-ALL). Minimal disease burden at entry and use of high-dose cyclophosphamide conditioning are reported to be associated with more favorable outcomes.

IntroductionFanconi anemia (FA) is a rare autosomal recessive cancer susceptibility syndrome characterized by developmental abnormalities, progressive bone marrow failure, and cellular hypersensitivity to DNA cross-linking agents. 1 Eleven FA complementation groups have been identified (A, B, C, D1, D2, E, F, G, I, J, and L) 2,3 and 8 FA genes have been cloned. 2,4,5 The FANCD1 gene is identical to the breast cancer susceptibility gene, BRCA2. 6 The 8 encoded FA proteins (A, C, D1, D2, E, F, G, L) cooperate in a common cellular pathway, the FA/BRCA pathway. 7 In this pathway, 6 of the FA proteins (A, C, E, F, G, L) 8,9 bind in a constitutive nuclear protein complex (the FA complex). In response to DNA damage 10 or during the S phase of the cell cycle, 11 the FA complex promotes the monoubiquitination of the downstream FANCD2 protein. This event requires a molecular interaction between the FANCE and FANCD2 proteins. 12,13 Monoubiquitination of FANCD2 is required for targeting of FANCD2 into nuclear foci containing BRCA1, FANCD1/ BRCA2, and RAD51. 11 These subnuclear foci may be sites of homologous recombination-mediated DNA repair, given the known roles of BRCA1, BRCA2, and RAD51 in this process. 14,15 Disruption of the FA/BRCA pathway results in the characteristic cellular and clinical features of FA, including hypersensitivity to DNA cross-linking agents. 16 A critical regulatory event in the FA/BRCA pathway is the monoubiquitination of FANCD2 on Lysine 561. 10 Analysis of FANCD2 monoubiquitination provides a rapid diagnostic screen for the integrity of the FA/BRCA pathway. 17 In addition, FANCD2 undergoes an ionizing radiation (IR)-inducible, ataxia telangiectasia (ATM)-dependent phosphorylation on Serine 222. 18 Phosphorylation of this serine is required for the establishment of an intra-S-phase checkpoint response but is not required for FANCD2 monoubiquitination, FANCD2 targeting to foci, or FANCD2-mediated DNA repair.Little is known about the regulation or functional outcome of FANCD2 monoubiquitination. First, the newly cloned FANCL protein has a plant homeodomain (PHD) domain with E3 ubiquitin ligase activity, although its ubiquitination of FANCD2 has not been demonstrated in vitro. 2 For personal use only. on May 12, 2018. by guest www.bloodjournal.org From monoubiquitinated isoform of FANCD2 (FANCD2-L) accumulates in discrete nuclear foci in damaged cells, 10 suggesting that it is actively transported to these structures. Accordingly, these foci may contain a specific receptor for FANCD2-L or its ubiquitin moiety. Third, following DNA repair or during the mitotic phase of the cell cycle, FANCD2-L is deubiquitinated, suggesting a reversible and more complex mechanism of regulation.The nucleus is organized into an integrated structure in which chromatin is associated with a nonhistone scaffold termed the nuclear matrix. 22 Various aspects of nucleic acid metabolism, including DNA replication, transcription, and the repair of UVinduced thymidine dimers, require an interaction between chromatin and the nu...

Hematopoietic stem cell transplant (HCT) recipients have a substantial risk of developing secondary solid cancers, particularly beyond 5 years after HCT and without reaching a plateau overtime. A working group was established through the Center for International Blood and Marrow Transplant Research and the European Group for Blood and Marrow Transplantation with the goal to facilitate implementation of cancer screening appropriate to HCT recipients. The working group reviewed guidelines and methods for cancer screening applicable to the general population and reviewed the incidence and risk factors for secondary cancers after HCT. A consensus approach was used to establish recommendations for individual secondary cancers. The most common sites include oral cavity, skin, breast and thyroid. Risks of cancers are increased after HCT compared with the general population in skin, thyroid, oral cavity, esophagus, liver, nervous system, bone and connective tissues. Myeloablative TBI, young age at HCT, chronic GVHD and prolonged immunosuppressive treatment beyond 24 months were well-documented risk factors for many types of secondary cancers. All HCT recipients should be advised of the risks of secondary cancers annually and encouraged to undergo recommended screening based on their predisposition. Here we propose guidelines to help clinicians in providing screening and preventive care for secondary cancers among HCT recipients.

The Fanconi anemia (FA) pathway is a DNA damage-activated signaling pathway which regulates cellular resistance to DNA cross-linking agents. Cloned FA genes and proteins cooperate in this pathway, and monoubiquitination of FANCD2 is a critical downstream event. The cell cycle checkpoint kinase ATR is required for the efficient monoubiquitination of FANCD2, while another checkpoint kinase, ATM, directly phosphorylates FANCD2 and controls the ionizing radiation (IR)-inducible intra-S-phase checkpoint. In the present study, we identify two novel DNA damage-inducible phosphorylation sites on FANCD2, threonine 691 and serine 717. ATR phosphorylates FANCD2 on these two sites, thereby promoting FANCD2 monoubiquitination and enhancing cellular resistance to DNA cross-linking agents. Phosphorylation of the sites is required for establishment of the intra-S-phase checkpoint response. IR-inducible phosphorylation of threonine 691 and serine 717 is also dependent on ATM and is more strongly impaired when both ATM and ATR are knocked down. Threonine 691 is phosphorylated during normal S-phase progression in an ATM-dependent manner. These findings further support the functional connection of ATM/ATR kinases and FANCD2 in the DNA damage response and support a role for the FA pathway in the coordination of the S phase of the cell cycle.Fanconi anemia (FA) is an autosomal recessive, or X-linked, cancer susceptibility disorder characterized by cellular hypersensitivity to DNA cross-linking agents, such as mitomycin C (MMC) (11, 12). The 11 cloned FA genes (A, B, C, D1, D2, E, F, G, L, M, and J) cooperate in a novel DNA damage response pathway, the FA pathway (6). Eight of the FA proteins (A, B, C, E, F, G, L, and M) are subunits of a nuclear E3 ubiquitin ligase required for monoubiquitination of the downstream FANCD2 protein on lysine 561, which is a critical step for the function of the FA pathway (8). The FANCL subunit is the putative catalytic E3 ligase subunit of the complex (19). Monoubiquitinated D2 interacts with FANCD1/BRCA2 (36). The recently cloned FANCJ protein is a helicase (3,15,16,18) which may work in concert with FANCD2-Ub and BRCA2 or may function independently of the FA pathway. Disruption of any of the proteins in the pathway leads to MMC hypersensitivity and chromosome instability.Increasing evidence supports a role for the FA pathway during normal S-phase progression in mammalian cells. First, the FA complex is associated with chromatin during S phase and interacts with the helicase BLM, suggesting that the complex plays a "sensor" role at the advancing replication fork (21, 22) Second, the newly cloned FANCM subunit of the FA complex appears to promote its chromatin association during S phase (20,26). Third, the FA complex activates FANCD2 monoubiquitination during S phase, leading to the association of monoubiquitinated FANCD2 with BRCA1 and RAD51 in replication foci (34). Fourth, the FA pathway is required for normal homologous recombination repair, a mode of DNA repair executed in S phase (28). Finally, t...

No abstract

The yeast mitochondrial protein Suv3p is a putative NTP-dependent RNA helicase. Here we report that in cells lacking Suv3p, there is an approximately 50-fold increase in the excised form of the group I intron omega of the mitochondrial 31S rRNA gene. Surprisingly, little mature 21S rRNA accumulates in those cells; instead, unligated 21S rRNA exons appear. Intron overaccumulation could lead to spliced exon reopening via a reaction known to be catalyzed by group I introns in vitro. We also show that Suv3p is a functional component of a novel mitochondrial NTP-dependent 3'-to-5' exoribonuclease activity that can degrade group I intron RNAs. These findings account for group I intron overaccumulation in cells lacking Suv3p and define a novel function for putative RNA helicases in direct RNA degradation.