Genetic and Functional Drivers of Diffuse Large B Cell Lymphoma.

Diffuse large B cell lymphoma (DLBCL) is the most common form of blood cancer and is characterized by a striking degree of genetic and clinical heterogeneity. This heterogeneity poses a major barrier to understanding the genetic basis of the disease and its response to therapy. Here, we performed an integrative analysis of whole-exome sequencing and transcriptome sequencing in a cohort of 1,001 DLBCL patients to comprehensively define the landscape of 150 genetic drivers of the disease. We characterized the functional impact of these genes using an unbiased CRISPR screen of DLBCL cell lines to define oncogenes that promote cell growth. A prognostic model comprising these genetic alterations outperformed current established methods: cell of origin, the International Prognostic Index comprising clinical variables, and dual MYC and BCL2 expression. These results comprehensively define the genetic drivers and their functional roles in DLBCL to identify new therapeutic opportunities in the disease.

The structure of an Hsp90-immunophilin complex reveals cochaperone recognition of the client maturation state.

The Hsp90 chaperone promotes folding and activation of hundreds of client proteins in the cell through an ATP-dependent conformational cycle guided by distinct cochaperone regulators. The FKBP51 immunophilin binds Hsp90 with its tetratricopeptide repeat (TPR) domain and catalyzes peptidyl-prolyl isomerase (PPIase) activity during folding of kinases, nuclear receptors, and tau. Here we determined the cryoelectron microscopy (cryo-EM) structure of the human Hsp90:FKBP51:p23 complex to 3.3 Å, which, together with mutagenesis and crosslinking analyses, reveals the basis for cochaperone binding to Hsp90 during client maturation. A helix extension in the TPR functions as a key recognition element, interacting across the Hsp90 C-terminal dimer interface presented in the closed, ATP conformation. The PPIase domain is positioned along the middle domain, adjacent to Hsp90 client binding sites, whereas a single p23 makes stabilizing interactions with the N-terminal dimer. With this architecture, FKBP51 is positioned to act on specific client residues presented during Hsp90-catalyzed remodeling.

Incidence and predictors of post-thrombotic syndrome in patients with proximal DVT in a real-world setting: findings from the GARFIELD-VTE registry.

Although substantial progress has been made in the pathophysiology and management of the post-thrombotic syndrome (PTS), several aspects still need clarification. Among them, the incidence and severity of PTS in the real world, the risk factors for its development, the value of patient's self-evaluation, and the ability to identify patients at risk for severe PTS. Eligible participants (n = 1107) with proximal deep-vein thrombosis (DVT) from the global GARFIELD-VTE registry underwent conventional physician's evaluation for PTS 36 months after diagnosis of their DVT using the Villalta score. In addition, 856 patients completed a Villalta questionnaire at 24 months. Variable selection was performed using stepwise algorithm, and predictors of severe PTS were incorporated into a multivariable risk model. The optimistic adjusted c-index was calculated using bootstrapping techniques. Over 36-months, 27.8% of patients developed incident PTS (mild in 18.7%, moderate in 5.7%, severe in 3.4%). Patients with incident PTS were older, had a lower prevalence of transient risk factors of DVT and a higher prevalence of persistent risk factors of DVT. Self-assessment of overall PTS at 24 months showed an agreement of 63.4% with respect to physician's evaluations at 36 months. The severe PTS multivariable model provided an optimistic adjusted c-index of 0.68 (95% CI 0.59-0.77). Approximately a quarter of DVT patients experienced PTS over 36 months after VTE diagnosis. Patient's self-assessment after 24 months provided added value for estimating incident PTS over 36 months. Multivariable risk analysis allowed good discrimination for severe PTS.

Allogeneic haematopoietic stem cell transplantation for myelofibrosis: prognostic indicators and the role of JAK2V617F measurable-residual disease monitoring by droplet-digital polymerase chain reaction.

Relapse after allogeneic haematopoietic stem cell transplantation (HSCT) is one of the key determinants of outcome in myelofibrosis (MF) and remains an important unmet need. In this retrospective single-centre study, we evaluated 35 consecutive patients with MF receiving allogeneic HSCT. At 30 days post-HSCT, full donor chimerism was achieved in 31 patients (88.6%). The median time to neutrophil engraftment was 16.8 (10-42) days and the median time to platelet engraftment was 26 (12-245) days. Four patients (11.4%) experienced primary graft failure. With a median duration of follow-up of 33 (1-223) months, with the 5-year overall survival (OS) and progression-free survival (PFS) were 51.6% and 46.3%, respectively. Relapse after HSCT (P < 0.001), leucocyte count ≥ 18 × 109/L at HSCT (P = 0.003) and accelerated/blast phase disease at HSCT (P < 0.001) were significantly associated with worse OS. Age at HSCT ≥ 54 years (P = 0.01), mutated ETV6 (P = 0.03), leucocyte count ≥ 18 × 109/L (P = 0.02), accelerated/blast phase MF (P = 0.001), and grade 2-3 bone marrow reticulin fibrosis at 12 months post-HSCT (P = 0.002) were significantly associated with worse PFS. JAK2V617F MRD ≥ 0.047 [sensitivity 85.7%; positive predictive value (PPV) 100%; AUC 0.984; P = 0.001] at 6 months and JAK2V617F MRD ≥ 0.009 (sensitivity 100%; PPV 100%; AUC 1.0; P = 0.001) at 12 months were highly predictive of post-HSCT relapse. Inferior OS and PFS were significantly associated with detectable JAK2V617F MRD at 12 months (P = 0.003 and P = 0.0001, respectively).

Spectrum of B-cell neoplasms associated with immunoglobulin G4-related disease.

Immunoglobulin G4-related disease (IgG4-RD) has rarely been associated with lymphoid neoplasms, the spectrum of which remains unclear. B-cell lymphoid neoplasms (LN) associated with IgG4-RD diagnosed in a 4-year period were analysed. There were five men and three women at a median age of 76.5 (52-90) years; three with synchronous IgG4-RD and LN; three with IgG4-RD preceding LN by 2, 3, and 22 years; and two with LN preceding IgG4-RD by 2.5 and 7 years. All patients presented with disseminated lymphadenopathy. Monoclonal gammopathy of undetermined significance (MGUS)/smouldering multiple myeloma (SMM) was found in three patients, all with an IgGκ paraprotein. Levels of IgGκ and IgG4 correlated. Diffuse large B-cell lymphoma (DLBCL) was found in three patients, with one case showing co-existing lymphoma and IgG4-RD in the same lymph node biopsy. The remaining two cases were marginal zone lymphoma (MZL) developing in a lacrimal gland previously involved by IgG4-RD; and nodular lymphocyte predominant Hodgkin lymphoma (NLP-HL) diagnosed in a lymph node with concomitant IgG4-RD. Low-dose continuous prednisolone was given for MGUS/SMM, with both monoclonal IgGκ and IgG4 responding. Combination chemotherapy was given for DLBCL, with two patients achieving complete response and one patient dying from refractory lymphoma. The patient with MZL refused treatment, whereas the case of NLP-HL responded completely to chemotherapy. Our findings together with previous observations suggest that IgG4-RD has an increased risk of B-cell neoplasms. Patients with IgG4-RD presenting with lymphadenopathy require vigorous investigations to exclude lymphoid neoplasms.

Ruxolitinib in the management of steroid-resistant/-dependent acute and chronic graft-versus-host disease: results of routine practice in an academic centre.

Graft-versus-host disease (GVHD) is an important complication after allogeneic haematopoietic stem cell transplantation (HSCT). Corticosteroids are the standard first-line treatment. Steroid-resistant/-dependent (SR/D) acute and chronic GVHD (aGVHD, cGVHD) lead to significant morbidity/mortality. The JAK2 inhibitor ruxolitinib has recently been shown in clinical trials to be effective in SR/D aGVHD and cGVHD. We retrospectively analysed the efficacy and safety of ruxolitinib in a cohort of SR/D aGVHD and cGVHD patients treated in a non-trial setting. In the aGVHD cohort, there were 14 men and 12 women, median age at 38 (19-63) years. At day 28 post-ruxolitinib, the overall response rate (ORR) was 86% (complete response, CR, 36%; partial response, PR, 50%). Continued ruxolitinib beyond day 28 resulted in a final CR of 68%. However, 3/15 (20%) of CR patients developed cGVHD. In the cGVHD cohort, there were 16 men and 15 women, median age at 33 (21-64) years. The ORR, CR and PR rates changed with continued ruxolitinib treatment, being 86%, 17% and 69% at 1 month; 79%, 38% and 41% at 3 months; and 83%, 52% and 31% at 6 months. Five patients had overlap GVHD, four of whom achieved CR. Multivariate analysis showed that superior overall survival and failure-free survival were associated with CR at day 28 for aGVHD, and CR at 1 year for cGVHD. Ruxolitinib treatment was efficacious for SR/D aGVHD and cGVHD, and continued treatment for at least 6 months was needed to maximize benefit.

Inhibition of C3 with pegcetacoplan results in normalization of hemolysis markers in paroxysmal nocturnal hemoglobinuria.

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired hematologic disorder characterized by complement-mediated hemolysis. C5 inhibitors (eculizumab/ravulizumab) control intravascular hemolysis but do not prevent residual extravascular hemolysis. The newly approved complement inhibitor, pegcetacoplan, inhibits C3, upstream of C5, and has the potential to improve control of complement-mediated hemolysis. The PADDOCK and PALOMINO clinical trials assessed the safety and efficacy of pegcetacoplan in complement inhibitor-naïve adults (≥ 18 years) diagnosed with PNH. Patients in PADDOCK (phase 1b open-label, pilot trial) received daily subcutaneous pegcetacoplan (cohort 1: 180 mg up to day 28 [n = 3]; cohort 2: 270-360 mg up to day 365 [n = 20]). PALOMINO (phase 2a, open-label trial) used the same dosing protocol as PADDOCK cohort 2 (n = 4). Primary endpoints in both trials were mean change from baseline in hemoglobin, lactate dehydrogenase, haptoglobin, and the number and severity of treatment-emergent adverse events. Mean baseline hemoglobin levels were below the lower limit of normal in both trials (PADDOCK: 8.38 g/dL; PALOMINO: 7.73 g/dL; normal range: 11.90-18.00 g/dL), increased to within normal range by day 85, and were sustained through day 365 (PADDOCK: 12.14 g/dL; PALOMINO: 13.00 g/dL). In PADDOCK, 3 serious adverse events (SAE) led to study drug discontinuation, 1 of which was deemed likely related to pegcetacoplan and 1 SAE, not deemed related to study drug, led to death. No SAE led to discontinuation/death in PALOMINO. Pegcetacoplan was generally well tolerated and improved hematological parameters by controlling hemolysis, while also improving other clinical PNH indicators in both trials. These trials were registered at www.clinicaltrials.gov (NCT02588833 and NCT03593200).

Epigenetic Silencing of PTEN and Epi-Transcriptional Silencing of MDM2 Underlied Progression to Secondary Acute Myeloid Leukemia in Myelodysplastic Syndrome Treated with Hypomethylating Agents.

In myelodysplastic syndrome (MDS), resistance to hypomethylating agents (HMA) portends a poor prognosis, underscoring the importance of understanding the molecular mechanisms leading to HMA-resistance. In this study, P39 and Kasumi-1 cells and their azacitidine-resistant and decitabine-resistant sublines were evaluated comparatively with transcriptomic and methylomic analyses. Expression profiling and genome-wide methylation microarray showed downregulation of PTEN associated with DNA hypermethylation in P39 cell lines resistant to azacitidine and decitabine. This pattern of PTEN dysregulation was also confirmed in a cohort of patients failing treatment with HMA. DNA hypomethylation of MDM2 was detected with downregulation of MDM2 in HMA resistant cell lines. Long-read sequencing revealed significant RNA hypomethylation of MDM2 resulting in alternative splicing and production of a truncated MDM2 transcript in azacitidine-resistant P39 cells. The expression of this MDM2 truncated transcript was also significantly increased in HMA-resistant patients compared with HMA-responsive patients. In conclusion, epigenetic and epi-transcriptomic dysregulation of PTEN and MDM2 were associated with resistance to hypomethylating agents.

Practical considerations for using K3 cameras in CDS mode for high-resolution and high-throughput single particle cryo-EM.

Detector technology plays a pivotal role in high-resolution and high-throughput cryo-EM structure determination. Compared with the first-generation, single-electron counting direct detection camera (Gatan K2), the latest K3 camera is faster, larger, and now offers a correlated-double sampling mode (CDS). Importantly this results in a higher DQE and improved throughput compared to its predecessor. In this study, we focused on optimizing camera data collection parameters for daily use within a cryo-EM facility and explored the balance between throughput and resolution. In total, eight data sets of murine heavy-chain apoferritin were collected at different dose rates and magnifications, using 9-hole image shift data collection strategies. The performance of the camera was characterized by the quality of the resultant 3D reconstructions. Our results demonstrated that the Gatan K3 operating in CDS mode outperformed standard (nonCDS) mode in terms of reconstruction resolution in all tested conditions with 8 electrons per pixel per second being the optimal dose rate. At low magnification (64kx) we were able to achieve reconstruction resolutions of 149% of the physical Nyquist limit (1.8 Å with a 1.346 Å physical pixel size). Low magnification allows more particles to be collected per image, aiding analysis of heterogeneous samples requiring large data sets. At moderate magnification (105kx, 0.834 Å physical pixel size) we achieved a resolution of 1.65 Å within 8-h of data collection, a condition optimal for achieving high-resolution on well behaved samples. Our results also show that for an optimal sample like apoferritin, one can achieve better than 2.5 Å resolution with 5 min of data collection. Together, our studies validate the most efficient ways of imaging protein complexes using the K3 direct detector and will greatly benefit the cryo-EM community.

Compromised function of the ESCRT pathway promotes endolysosomal escape of tau seeds and propagation of tau aggregation.

Intercellular propagation of protein aggregation is emerging as a key mechanism in the progression of several neurodegenerative diseases, including Alzheimer's disease and frontotemporal dementia (FTD). However, we lack a systematic understanding of the cellular pathways controlling prion-like propagation of aggregation. To uncover such pathways, here we performed CRISPR interference (CRISPRi) screens in a human cell-based model of propagation of tau aggregation monitored by FRET. Our screens uncovered that knockdown of several components of the endosomal sorting complexes required for transport (ESCRT) machinery, including charged multivesicular body protein 6 (CHMP6), or CHMP2A in combination with CHMP2B (whose gene is linked to familial FTD), promote propagation of tau aggregation. We found that knocking down the genes encoding these proteins also causes damage to endolysosomal membranes, consistent with a role for the ESCRT pathway in endolysosomal membrane repair. Leakiness of the endolysosomal compartment significantly enhanced prion-like propagation of tau aggregation, likely by making tau seeds more available to pools of cytoplasmic tau. Together, these findings suggest that endolysosomal escape is a critical step in tau propagation in neurodegenerative diseases.

Oral arsenic trioxide, all-trans retinoic acid, and ascorbic acid maintenance after first complete remission in acute promyelocytic leukemia: Long-term results and unique prognostic indicators.

BACKGROUND: The role of arsenic trioxide (As2 O3 ) in the maintenance of first complete remission (CR1) in acute promyelocytic leukemia (APL) is unclear. METHODS: A total of 129 consecutive adult patients with APL of all risk categories who achieved CR1 with conventional induction (all-trans retinoic acid [ATRA]/daunorubicin) and consolidation (daunorubicin/cytarabine [induction daunorubicin and consolidation omitted for age ≥70 years]) underwent maintenance comprising ATRA (45 mg/m2 /day), oral As2 O3 (10 mg/day), and ascorbic acid (1 g/day) (AAA) for 2 weeks every 2 months for 2 years. RESULTS: Over a 17-year period from August 1, 2002, to July 31, 2019, 63 men and 66 women (median age, 46 years [range, 18-82 years]) received AAA maintenance, which was already completed in 117 patients. At a median follow-up of 100 months (range, 8-215 months), 17 patients (13%) developed first relapse (R1) (hematologic, n = 14; molecular, n = 3) after a median of 19 months (range, 7-96 months) from CR1. Two R1 patients had concomitant central nervous system (CNS) involvement. All patients achieved CR2 with oral As2 O3 -based salvage. Five patients had a subsequent relapse and died. Eight patients died of unrelated causes while still in CR1. The 5-year and 10-year rates of relapse-free survival (RFS) were 89% and 85%, respectively. The 5-year and 10-year rates of overall survival (OS) were 94% and 87%, respectively. Multivariate analysis showed that inferior RFS was associated with FLT3-ITD (P = .005) and CNS involvement on presentation (P = .004), and inferior OS was associated with therapy-related APL (P = .03), FLT3-ITD (P = .03), and relapse (P = .03). The safety profile was favorable, with no grade 3/4 organ toxicities. CONCLUSION: CR1 maintenance with AAA is safe and results in favorable long-term survival in patients with APL.

Low-dose pembrolizumab and nivolumab were efficacious and safe in relapsed and refractory classical Hodgkin lymphoma: Experience in a resource-constrained setting.

The efficacy and safety of low-dose anti-PD1 antibodies in relapsed/refractory classical Hodgkin lymphoma (cHL) require confirmation. Pembrolizumab (100 mg every 3 weeks, Q3W) or nivolumab (40 mg Q2W) were administered to patients with relapsed/refractory cHL. In the pembrolizumab cohort (N = 11), who had failed a median of three (1-6) therapies (brentuximab vedotin [BV]: 91%; autologous hematopoietic stem cell transplantation [auto-HSCT]: 18%), the overall response rate (ORR) by positron emission tomography-computed tomography was 100% (metabolic complete response [mCR]: 73%; partial response [PR]: 27%). Median cumulative dose for achieving best response was 400 (300-800) mg. Median progression-free survival (PFS) was 35 months. Median overall survival (OS) was not reached. Adverse events (AEs) of grade 1-2 were observed in three patients. In the nivolumab cohort (N = 6), who had failed a median of three (2-6) therapies (BV: 50%; auto-HSCT: 17%; allogeneic HSCT: 34%), the ORR was 100% (mCR: 67%; PR: 17%; indeterminate response: 17%). Median cumulative dose for achieving best response was 160 (160-360) mg. Median PFS was 33 months. Median OS was not reached. AEs of grade 1-2 were observed in four patients, two of whom had pre-existing autoimmune conditions. Five patients with Epstein-Barr virus (EBV) positive Reed-Sternberg cells underwent monitoring of plasma EBV DNA, which became negative in four mCR patients but remained positive in one PR patient who died ultimately from refractory lymphoma. Low-dose pembrolizumab and nivolumab were highly efficacious and safe in relapsed/refractory cHL. These observations have significant financial implications in resource-constrained settings.

X-linked inhibitor of apoptosis protein (XIAP) is a client of heat shock protein 70 (Hsp70) and a biomarker of its inhibition.

Heat shock protein 70 (Hsp70) and Hsp90 are molecular chaperones that play essential roles in tumor growth by stabilizing pro-survival client proteins. However, although the development of Hsp90 inhibitors has benefited from the identification of clients, such as Raf-1 proto-oncogene, Ser/Thr kinase (RAF1), that are particularly dependent on this chaperone, no equivalent clients for Hsp70 have been reported. Using chemical probes and MDA-MB-231 breast cancer cells, we found here that the inhibitors of apoptosis proteins, including c-IAP1 and X-linked inhibitor of apoptosis protein (XIAP), are obligate Hsp70 clients that are rapidly (within ∼3-12 h) lost after inhibition of Hsp70 but not of Hsp90. Mutagenesis and pulldown experiments revealed multiple Hsp70-binding sites on XIAP, suggesting that it is a direct, physical Hsp70 client. Interestingly, this interaction was unusually tight (∼260 nm) for an Hsp70-client interaction and involved non-canonical regions of the chaperone. Finally, we also found that Hsp70 inhibitor treatments caused loss of c-IAP1 and XIAP in multiple cancer cell lines and in tumor xenografts, but not in healthy cells. These results are expected to significantly accelerate Hsp70 drug discovery by providing XIAP as a pharmacodynamic biomarker. More broadly, our findings further suggest that Hsp70 and Hsp90 have partially non-overlapping sets of obligate protein clients in cancer cells.

PD1 blockade with pembrolizumab is highly effective in relapsed or refractory NK/T-cell lymphoma failing l-asparaginase.

Natural killer (NK)/T-cell lymphomas failing L-asparaginse regimens have no known salvage and are almost invariably fatal. Seven male patients with NK/T-cell lymphoma (median age, 49 years; range, 31-68 years) for whom a median of 2 (range, 1-5) regimens (including l-asparaginase regimens and allogeneic hematopoietic stem-cell transplantation [HSCT] in 2 cases) failed were treated with the anti-programmed death 1 (PD1) antibody pembrolizumab. All patients responded, according to various clinical, radiologic (positron emission tomography), morphologic, and molecular (circulating Epstein-Barr virus [EBV] DNA) criteria. Two patients achieved complete response (CR) in all parameters. Three patients achieved clinical and radiologic CRs, with two having molecular remission (undetectable EBV DNA) but minimal EBV-encoded RNA-positive cells in lesions comprising predominantly CD3+CD4+ and CD3+CD8+ T cells (which ultimately disappeared, suggesting they represented pseudoprogression) and one having detectable EBV DNA despite morphologic CR. Two patients achieved partial response (PR). After a median of 7 (range, 2-13) cycles of pembrolizumab and a follow-up of a median of 6 (range, 2-10) months, all five CR patients were still in remission. The only adverse event was grade 2 skin graft-versus-host disease in one patient with previous allogeneic HSCT. Expression of the PD1 ligand was strong in 4 patients (3 achieving CR) and weak in 1 (achieving PR). PD1 blockade with pembrolizumab was a potent strategy for NK/T-cell lymphomas failing l-asparaginase regimens.

Rapid versus gradual lung function decline in bronchiolitis obliterans syndrome after haematopoietic stem cell transplantation is associated with survival outcome.

BACKGROUND AND OBJECTIVE: Bronchiolitis obliterans syndrome (BOS) after haematopoietic stem cell transplantation (HSCT) presents with lung function decline. The pattern of lung function decline after BOS diagnosis could impact prognostication of BOS as a complication after HSCT. The aim of this study was to assess the impact of lung function decline on overall survival (OS) in BOS subjects. METHODS: Subjects with BOS were compared to those without BOS and matched for age, gender, primary diagnoses, conditioning regimes and chronic graft versus host disease. Lung function tests at baseline, at BOS diagnosis and every 3 months after HSCT were evaluated. RESULTS: Of the 1461 subjects undergoing allogeneic HSCT (allo-HSCT) between 1998 and 2015, 95 (6.5%) were diagnosed with BOS. A total of 159 matched HSCT recipients without BOS were identified. A 25% decline in FEV1 within the first 3 months after BOS diagnosis would separate BOS subjects into a subgroup with initial rapid decline and another subgroup with initial gradual decline in lung function. The rapid decline group showed lower subsequent lung function parameters and significantly worse OS compared to the gradual decline group (P = 0.013). CONCLUSION: Post-HSCT BOS subjects with initial rapid lung function decline within 3 months after BOS diagnosis will have significantly poorer lung function and worse OS compared to those with initial gradual decline in lung function after BOS diagnosis. HSCT BOS patients with rapid initial decline in lung function warrant closer monitoring for the development of other post-HSCT complications that could affect their survival.

The peptidyl-prolyl isomerase PIN1 relieves cyclin-dependent kinase 2 (CDK2) inhibition by the CDK inhibitor p27.

PIN1 is a peptidyl-prolyl isomerase that catalyzes the cis/trans isomerization of peptide bonds between proline and phosphorylated serine/threonine residues. By changing the conformation of its protein substrates, PIN1 increases the activities of key proteins that promote cell cycle progression and oncogenesis. Moreover, it has been shown that PIN1 stabilizes and increases the level of the cyclin-dependent kinase (CDK) inhibitor p27, which inhibits cell cycle progression by binding cyclin A- and cyclin E-CDK2. Notwithstanding the associated increase in the p27 level, PIN1 expression promotes rather than retards cell proliferation. To explain the paradoxical effects of PIN1 on p27 levels and cell cycle progression, we hypothesized that PIN1 relieves CDK2 inhibition by suppressing the CDK inhibitory activity of p27. Here, we confirmed that PIN1-expressing cells exhibit higher p27 levels but have increased CDK2 activities and higher proliferation rates in the S-phase compared with Pin1-null fibroblasts or PIN1-depleted hepatoma cells. Using co-immunoprecipitation and CDK kinase activity assays, we found that PIN1 binds the phosphorylated Thr187-Pro motif in p27 and reduces p27's interaction with cyclin A- or cyclin E-CDK2, leading to increased CDK2 kinase activity. In conclusion, our results indicate that although PIN1 increases p27 levels, it also attenuates p27's inhibitory activity on CDK2 and thereby contributes to increased G1-S phase transitions and cell proliferation.

Long-term outcome of relapsed acute promyelocytic leukemia treated with oral arsenic trioxide-based reinduction and maintenance regimens: A 15-year prospective study.

BACKGROUND: For patients who have acute promyelocytic leukemia (APL) in second complete remission (CR2), optimal postremission strategies remain undefined. METHODS: The role of an oral arsenic trioxide (As2 O3 )-based regimen in the management of patients who had APL in CR2 was examined. RESULTS: Seventy-three patients with APL in first relapse (R1) were studied. Oral As2 O3 -based reinduction resulted uniformly in CR2, irrespective of previous As2 O3 exposure. All patients received oral As2 O3 -based maintenance in CR2. At a median follow-up of 94 months (range, 9-205 months), 43 patients (58.9%) were still in CR2, and 49 (67.1%) had finished the planned 2-year CR2 maintenance with all-trans retinoic acid, oral As2 O3 , and ascorbic acid. Reinduction and maintenance treatments were well tolerated. Grade 1 and 2 headache occurred in 20 patients (27.4%). Hepatotoxicity, all in the form of transaminitis, occurred in 35 patients (47.9%; grade 1 and 2, n = 26; grade 3 and 4, n = 9). Three patients had self-limiting QTc prolongation. The 10-year leukemia-free survival rate was 56.8%. Thirty patients developed R2. Oral As2 O3 -based reinduction led to CR3 in 27 patients (90%). Post-CR3 strategies included autologous hematopoietic stem cell transplantation and oral As2 O3 maintenance. At a post-CR3 follow-up of 30 months (range, 3-166 months), 11 patients were still in CR3. The 5-year and 10-year overall survival rates in the R1 cohort were 79.5% and 67.3%, respectively. Prior receipt of oral As2 O3 maintenance in CR1 was the only risk factor for inferior leukemia-free survival. Central nervous system involvement occurred in 15 patients, including 5 who remained alive. Relapse during oral As2 O3 therapy was the only significant risk factor for central nervous system involvement. CONCLUSIONS: For patients with relapsed APL, As2 O3 remained effective despite repeated As2 O3 exposures. Oral As2 O3 maintenance was an effective postremission strategy for CR2. Cancer 2018;124:2316-26. © 2018 American Cancer Society.

Cell Cycle-Dependent Uptake and Cytotoxicity of Arsenic-Based Drugs in Single Leukemia Cells.

Arsenic has long been used as therapeutic agents. Understanding the mechanism of action of arsenic-based drugs enables more effective arsenic drugs to be developed. Cell cycle has been known to play a critical role for cell division and growth. Herein, we establish a methodology to evaluate the uptake of two arsenic-based drugs (ATO and ZIO-101) across the cell cycle in single leukemia cells, i.e., NB4 and HL60, using a double thymidine block combined with time-resolved inductively coupled plasma mass spectrometry (ICPMS). We show that cells absorb maximal amounts of both ATO and ZIO-101 in G2/M phase and minimum in S phase, and such variation is less apparent for ZIO-101 than ATO (NB4-G2/M:S = 2.5:1 for ATO and 1.6:1 for ZIO-101). We subsequently demonstrate that AQP9, an ATO transporter, is highly expressed in the G1 phase (50.2-46.9%) and minimum value was observed in the S phase (27.6-24.6%); whereas xCT, a ZIO-101 transporter, is maximally expressed in the G2/M phase (74.8-76.1%) and minimally expressed in the G1 phases (55.4-59.8%). Different expression levels of AQP9 and xCT are only partially accountable for the observed differences in arsenic uptake across cell cycle, indicative of the presence of other importers for both ATO and ZIO-101. Furthermore, we show that the cytotoxicity of ATO and ZIO-101 on NB4 cells is also cell cycle dependent, with the highest cytotoxicity at S + G2/M phase and the lowest at G1 + S phase. Our studies provide the first evidence on cell cycle dependent uptake and cytotoxicity of arsenic-based drugs at single cell levels, may have general implications for precise evaluation of other anticancer drugs by considering cell cycle phase.

Deficiency of Cks1 Leads to Learning and Long-Term Memory Defects and p27 Dependent Formation of Neuronal Cofilin Aggregates.

In mitotic cells, the cyclin-dependent kinase (CDK) subunit protein CKS1 regulates S phase entry by mediating degradation of the CDK inhibitor p27. Although mature neurons lack mitotic CDKs, we found that CKS1 was actively expressed in post-mitotic neurons of the adult hippocampus. Interestingly, Cks1 knockout (Cks1-/-) mice exhibited poor long-term memory, and diminished maintenance of long-term potentiation in the hippocampal circuits. Furthermore, there was neuronal accumulation of cofilin-actin rods or cofilin aggregates, which are associated with defective dendritic spine maturation and synaptic loss. We further demonstrated that it was the increased p27 level that activated cofilin by suppressing the RhoA kinase-mediated inhibitory phosphorylation of cofilin, resulting in the formation of cofilin aggregates in the Cks1-/- neuronal cells. Consistent with reports that the peptidyl-prolyl-isomerase PIN1 competes with CKS1 for p27 binding, we found that inhibition of PIN1 diminished the formation of cofilin aggregates through decreasing p27 levels, thereby activating RhoA and increasing cofilin phosphorylation. Our results revealed that CKS1 is involved in normal glutamatergic synapse development and dendritic spine maturation in adult hippocampus through modulating p27 stability.

Prevalence of mild behavioral impairment in mild cognitive impairment and subjective cognitive decline, and its association with caregiver burden.

BACKGROUND: Mild behavioral impairment (MBI) describes later life acquired, sustained neuropsychiatric symptoms (NPS) in cognitively normal individuals or those with mild cognitive impairment (MCI), as an at-risk state for incident cognitive decline and dementia. We developed an operational definition of MBI and tested whether the presence of MBI was related to caregiver burden in patients with subjective cognitive decline (SCD) or MCI assessed at a memory clinic. METHODS: MBI was assessed in 282 consecutive memory clinic patients with SCD (n = 119) or MCI (n = 163) in accordance with the International Society to Advance Alzheimer's Research and Treatment - Alzheimer's Association (ISTAART-AA) research diagnostic criteria. We operationalized a definition of MBI using the Neuropsychiatric Inventory Questionnaire (NPI-Q). Caregiver burden was assessed using the Zarit caregiver burden scale. Generalized linear regression was used to model the effect of MBI domains on caregiver burden. RESULTS: While MBI was more prevalent in MCI (85.3%) than in SCD (76.5%), this difference was not statistically significant (p = 0.06). Prevalence estimates across MBI domains were affective dysregulation (77.8%); impulse control (64.4%); decreased motivation (51.7%); social inappropriateness (27.8%); and abnormal perception or thought content (8.7%). Affective dysregulation (p = 0.03) and decreased motivation (p=0.01) were more prevalent in MCI than SCD patients. Caregiver burden was 3.35 times higher when MBI was present after controlling for age, education, sex, and MCI (p < 0.0001). CONCLUSIONS: MBI was common in memory clinic patients without dementia and was associated with greater caregiver burden. These data show that MBI is a common and clinically relevant syndrome.