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Introduction: Chemoradiotherapy (CRT) is the standard of care in inoperable non-small-cell lung cancer (NSCLC) patients, favoring concurrent (cCRT) over sequential CRT (seqCRT), with adjuvant immunotherapy in responders. Elderly and frail NSCLC patients have generally been excluded from trials in the past. In elderly patients however, the higher treatment related morbidity of cCRT, may outweigh the possible lower tumor control of seqCRT. For elderly patients with locally advanced NSCLC real-world data is essential to be able to balance treatment toxicity and treatment outcome. The aim of this study is to analyze acute toxicity and 3-month mortality of curative chemoradiation (CRT) in patients with stage III NSCLC and to analyze whether cCRT for elderly stage III NSCLC patients is safe., Methods: The Dutch Lung Cancer Audit-Radiotherapy (DLCA-R) is a national lung cancer audit that started in 2013 for patients treated with curative intent radiotherapy. All Dutch patients treated for stage III NSCLC between 2015 and 2018 with seqCRT or cCRT for (primary or recurrent) stage III lung cancer are included in this population-based study. Information was collected on patient, tumor- and treatment characteristics and the incidence and severity of acute non-hematological toxicity (CTCAE-4 version 4.03) and mortality within 3 months after the end of radiotherapy. To evaluate the association between prognostic factors and outcome (acute toxicity and mortality within 3 months), an univariable and multivariable analysis was performed. The definition of cCRT was:radiotherapy started within 30 days after the start of chemotherapy., Results: Out of all 20 Dutch departments of radiation oncology, 19 centers participated in the registry. A total of 2942 NSCLC stage III patients were treated with CRT. Of these 67.2% (n = 1977) were treated with cCRT (median age 66 years) and 32.8% (n = 965) were treated with seqCRT (median age 69 years). Good performance status (WHO 0-1) was scored in 88.6% for patients treated with cCRT and in 71.0% in the patients treated with seqCRT. Acute nonhematological 3-month toxicity (CTCAE grade ≥3 or radiation pneumonitis grade ≥2) was scored in 21.9% of the patients treated with cCRT and in 17.7% of the patients treated with seqCRT. The univariable analysis for acute toxicity showed significantly increased toxicity for cCRT (P = .008), WHO ≥2 (P = .006), and TNM IIIC (P = .031). The multivariable analysis for acute toxicity was significant for cCRT (P = .015), WHO ≥2 (P = .001) and TNM IIIC (P = .016). The univariable analysis for 3-month mortality showed significance for seqCRT (P = .025), WHO ≥2 (P < .001), higher cumulative radiotherapy dose (P < .001), higher gross tumor volume total (P = .020) and male patients (p < .001). None of these variables reached significance in the multivariable analysis for 3-month mortality., Conclusion: In this national lung cancer audit of inoperable NSCLC patients, 3-month toxicity was significantly higher in patients treated with cCRT (21.9% vs. 17.7% for seqCRT) higher TNM stage IIIC, and poor performance (WHO≥2) patients.The 3-months mortality was not significantly different for tested parameters. Age was not a risk factor for acute toxicity, nor 3 months mortality., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)

The number of hematopoietic stem cells (HSCs) that contributes to blood formation and the dynamics of their clonal contribution is a matter of ongoing discussion. Here, we use cellular barcoding combined with multiplex high-throughput sequencing to provide a quantitative and sensitive analysis of clonal behavior of hundreds of young and old HSCs. The majority of transplanted clones steadily contributes to hematopoiesis in the long-term, although clonal output in granulocytes, T cells, and B cells is substantially different. Contributions of individual clones to blood are dynamically changing; most of the clones either expand or decline with time. Finally, we demonstrate that the pool of old HSCs is composed of multiple small clones, whereas the young HSC pool is dominated by fewer, but larger, clones.

Background: Several French, Belgian and Dutch radiation oncologists have reported good results with the combination of limited surgery after external beam radiotherapy (EBRT) followed by brachytherapy in early-stage muscle-invasive bladder cancer., Patients and Methods: Data from 12 of 13 departments which are using this approach have been collected retrospectively, in a multicenter database, resulting in 1040 patients: 811 males and 229 females with a median age of 66 years, range 28-92 years. Results were analyzed according to tumor stage and diameter, histology grade, age and brachytherapy technique, continuous low-dose rate (CLDR) and pulsed dose rate (PDR)., Results: At 1, 3 and 5 years, the local recurrence-free probability was 91%, 80% and 75%, metastasis-free probability was 91%, 80% and 74%, disease-free probability was 85%, 68% and 61% and overall survival probability was 91%, 74% and 62%, respectively. The differences in the outcome between the contributing departments were small. After multivariate analysis, the only factor influencing the local control rate was the brachytherapy technique. Toxicity consisted mainly of 24 fistula, 144 ulcers/necroses and 93 other types., Conclusions: EBRT followed by brachytherapy, combined with limited surgery, offers excellent results in terms of bladder sparing for selected groups of patients suffering from bladder cancer.

Increased expression of Kruppel-like factor 7 (KLF7) is an independent predictor of poor outcome in pediatric acute lymphoblastic leukemia. The contribution of KLF7 to hematopoiesis has not been previously described. Herein, we characterized the effect on murine hematopoiesis of the loss of KLF7 and enforced expression of KLF7. Long-term multilineage engraftment of Klf7(-/-) cells was comparable with control cells, and self-renewal, as assessed by serial transplantation, was not affected. Enforced expression of KLF7 results in a marked suppression of myeloid progenitor cell growth and a loss of short- and long-term repopulating activity. Interestingly, enforced expression of KLF7, although resulting in multilineage growth suppression that extended to hematopoietic stem cells and common lymphoid progenitors, spared T cells and enhanced the survival of early thymocytes. RNA expression profiling of KLF7-overexpressing hematopoietic progenitors identified several potential target genes mediating these effects. Notably, the known KLF7 target Cdkn1a (p21(Cip1/Waf1)) was not induced by KLF7, and loss of CDKN1A does not rescue the repopulating defect. These results suggest that KLF7 is not required for normal hematopoietic stem and progenitor function, but increased expression, as seen in a subset of lymphoid leukemia, inhibits myeloid cell proliferation and promotes early thymocyte survival.

Despite increasing knowledge on the regulation of hematopoietic stem/progenitor cell (HSPC) self-renewal and differentiation, in vitro control of stem cell fate decisions has been difficult. The ability to inhibit HSPC commitment in culture may be of benefit to cell therapy protocols. Small molecules can serve as tools to manipulate cell fate decisions. Here, we tested 2 small molecules, valproic acid (VPA) and lithium (Li), to inhibit differentiation. HSPCs exposed to VPA and Li during differentiation-inducing culture preserved an immature cell phenotype, provided radioprotection to lethally irradiated recipients, and enhanced in vivo repopulating potential. Anti-differentiation effects of VPA and Li were observed also at the level of committed progenitors, where VPA re-activated replating activity of common myeloid progenitor and granulocyte macrophage progenitor cells. Furthermore, VPA and Li synergistically preserved expression of stem cell-related genes and repressed genes involved in differentiation. Target genes were collectively co-regulated during normal hematopoietic differentiation. In addition, transcription factor networks were identified as possible primary regulators. Our results show that the combination of VPA and Li potently delays differentiation at the biologic and molecular levels and provide evidence to suggest that combinatorial screening of chemical compounds may uncover possible additive/synergistic effects to modulate stem cell fate decisions.

Hematopoietic stem/progenitor cell (HSPC) traits differ between genetically distinct mouse strains. For example, DBA/2 mice have a higher HSPC frequency compared with C57BL/6 mice. We performed a genetic screen for micro-RNAs that are differentially expressed between LSK, LS(-)K(+), erythroid and myeloid cells isolated from C57BL/6 and DBA/2 mice. This analysis identified 131 micro-RNAs that were differentially expressed between cell types and 15 that were differentially expressed between mouse strains. Of special interest was an evolutionary conserved miR cluster located on chromosome 17 consisting of miR-99b, let-7e, and miR-125a. All cluster members were most highly expressed in LSKs and down-regulated upon differentiation. In addition, these microRNAs were higher expressed in DBA/2 cells compared with C57BL/6 cells, and thus correlated with HSPC frequency. To functionally characterize these microRNAs, we overexpressed the entire miR-cluster 99b/let-7e/125a and miR-125a alone in BM cells from C57BL/6 mice. Overexpression of the miR-cluster or miR-125a dramatically increased day-35 CAFC activity and caused severe hematopoietic phenotypes upon transplantation. We showed that a single member of the miR-cluster, namely miR-125a, is responsible for the majority of the observed miR-cluster overexpression effects. Finally, we performed genome-wide gene expression arrays and identified candidate target genes through which miR-125a may modulate HSPC fate.

The major limitation for the development of curative cancer therapies has been an incomplete understanding of the molecular mechanisms driving cancer progression. Human models to study the development and progression of chronic myeloid leukemia (CML) have not been established. Here, we show that BMI1 collaborates with BCR-ABL in inducing a fatal leukemia in nonobese diabetic/severe combined immunodeficiency mice transplanted with transduced human CD34(+) cells within 4-5 months. The leukemias were transplantable into secondary recipients with a shortened latency of 8-12 weeks. Clonal analysis revealed that similar clones initiated leukemia in primary and secondary mice. In vivo, transformation was biased toward a lymphoid blast crisis, and in vitro, myeloid as well as lymphoid long-term, self-renewing cultures could be established. Retroviral introduction of BMI1 in primary chronic-phase CD34(+) cells from CML patients elevated their proliferative capacity and self-renewal properties. Thus, our data identify BMI1 as a potential therapeutic target in CML.

Since endotoxins are potent inducers of stem cell mobilization, we hypothesized that their presence in the gut may play a role in cytokine-induced mobilization. To address this possibility we added ciprofloxacin and polymyxin B to the drinking water of Balb/c mice mobilized with either interleukin-8 (IL-8), granulocyte colony-stimulating factor (G-CSF), or flt3 ligand (FL). The yield of colony-forming units (CFUs) was significantly reduced in all mice treated with these antibiotics when compared with controls (IL-8: 192 +/- 61 vs 290 +/- 64, P <.05; G-CSF: 1925 +/- 1216 vs 3371 +/- 1214, P <.05; FL: 562 +/- 213 vs 1068 +/- 528, P <.05). Treatment with ciprofloxacin eliminated only aerobic Gram-negative bacteria from the feces without effect on mobilization. Polymyxin B treatment did not result in decontamination but significantly reduced the number of mobilized hematopoietic progenitor cells (HPCs) most likely due to the endotoxin binding capacity of polymyxin B. More than 90% of the gastrointestinal flora consists of anaerobic bacteria. Elimination of the anaerobic flora by metronidazol led to a significantly reduced number of mobilized HPCs when compared with controls (IL-8: 55 +/- 66 vs 538 +/- 216, P <.05). Germ-free OF1 mice showed a significantly reduced mobilization compared with their wild-type controls (IL-8 controls: 378 +/- 182, IL-8 germ free: 157 +/- 53, P <.05). Finally, we performed reconstitution experiments adding Escherichia coli-derived endotoxins to the drinking water of decontaminated mice. This resulted in partial restoration of the IL-8-induced mobilization (67 +/- 28 vs 190 +/- 98.1, P <.01). Our results indicate that endotoxins serve as cofactors in cytokine-induced mobilization. Modification of the endotoxin content by antibiotic treatment may affect the yield of cytokine-induced mobilization.

The beta 2 integrins leukocyte function antigen-1 (LFA-1, CD11a) and macrophage antigen-1 (Mac-1, CD11b) have been reported to play a role in the attachment of CD34(+) cells to stromal cells in the bone marrow. When administered prior to interleukin-8 (IL-8), anti-LFA-1 antibodies completely prevent the IL-8-induced mobilization of hematopoietic stem cells in mice. Here, we studied the role of anti-beta 2 integrin antibodies in granulocyte colony-stimulating factor (G-CSF)-induced mobilization of hematopoietic progenitor cells. Administration of antibodies against the alpha chain of LFA-1 or against the alpha chain of Mac-1 followed by daily injections of G-CSF for more than 1 day resulted in a significant enhancement of mobilization of hematopoietic progenitor cells when compared with mobilization induced by G-CSF alone. Also, the number of late (day 28) cobblestone area-forming cells in vitro was significantly higher after mobilization with anti-LFA-1 antibodies followed by 5 microg G-CSF for 5 days than with G-CSF alone (119 +/- 34 days vs 17 +/- 14 days), indicating mobilization of repopulating stem cells. Pretreatment with blocking antibodies to intercellular adhesion molecule-1 (ICAM-1; CD54), a ligand of LFA-1 and Mac-1, did not result in an effect on G-CSF-induced mobilization, suggesting that the enhancing effect required an interaction of the beta 2 integrins and one of their other ligands. Enhancement of mobilization was not observed in LFA-1-deficient (CD11a) mice, indicating that activated cells expressing LFA-1 mediate the synergistic effect, rather than LFA-1-mediated adhesion.

Despite the increasing use of cytokines to circumvent the acute dose-limiting myelotoxicity of cancer treatment, little is known about the combined effects of cytotoxic agents and cytokines on the primitive stem cells responsible for long-term hematopoiesis. In an experimental model, we administered cytotoxic agents that have variable effects on primitive stem cells in C57BL/6 (B6)-mice. Mice received six every-other-week doses of cyclophosphamide (CY, 84 mg/kg), VP-16 (24 mg/kg) + cisplatinum (2.4 mg/kg), carboplatinum (50 mg/kg), chlorambucil (12 mg/kg), BCNU (13.2 mg/kg), or TBI (80 cGy). Granulocyte colony-stimulating factor (G-CSF; 250 microg/kg/day) was administered subcutaneously twice daily on days 3 to 6 after each dose of the cytotoxic agent. Comparison with animals receiving the cytotoxic agent alone was made to investigate the effects of G-CSF on long-term hematopoiesis. Hematopoiesis was measured 20 weeks after the last dose of the cytotoxic agent by assessment of peripheral blood counts, marrow cellularity, progenitor cell content (colony-forming units-spleen; CFU-S), and primitive stem cell number (long-term repopulating ability and day 28 and day 35 cobblestone area-forming cell [CAFC] frequencies). Exposure to cytotoxic agents alone resulted in a significant decrease in primitive stem cells (as measured by repopulating units [RU] and day 28 and day 35 CAFC content) in animals given carboplatinum, chlorambucil, BCNU, and TBI, but not in animals treated with cyclophosphamide or VP-16 and cisplatinum. The addition of G-CSF resulted in a significant decrease in stem cell content when compared with no G-CSF administration in animals treated with chlorambucil, BCNU, or TBI. Thus, G-CSF administered after repeated exposure to cytotoxic agents, appeared to damage the primitive stem cell compartment when used in combination with agents known to damage primitive stem cells. These results, although obtained in an experimental model, should raise concerns for the indiscriminate use of G-CSF in the clinic., (Copyright 1998 by The American Society of Hematology.)

Administration of kit-ligand (KL) before and after doses of 5-fluorouracil (5-FU) results in marrow failure in mice, presumably because of enhanced KL-induced cycling of stem cells, which makes them more susceptible to the effects of 5-FU. In attempt to capitalize on this effect on stem cells, we studied the ability of KL and 5-FU to allow stable donor engraftment of congenically marked marrow in a C57BL/6 (B6) mouse model. KL was administered subcutaneously at 50 microg/kg, 21 hours and 9 hours before and 3 hours after each of two doses of 5-FU (125 mg/kg) given 7 days apart to B6-recipients. Animals then received three injections of 10(7) congenic B6-Gpi-1a-donor bone marrow cells at 24, 48, and 72 hours after the second 5-FU dose. A separate group of animals received a single dose of either 1 x 10(7) or 3 x 10(7) donor marrow cells 24 hours after the last 5-FU dose. The level of engraftment was measured from Gpi-phenotyping at 1, 3, 6, and 8 months in red blood cells (RBCs) and at 8 months by phenotyping cells from the thymus, spleen, and marrow. Percent donor engraftment in RBCs appeared stable after 6 months. The percent donor engraftment in RBCs at 8 months was significantly higher in KL + 5-FU prepared recipients (33.0 +/- 2.7), compared with 5-FU alone (18.5 +/- 2.6, P < .0005), or saline controls (17.8 +/- 1.7, P < .0001). In an additional experiment, granulocyte colony-stimulating factor (100 microg/dose) was added to a reduced dose of KL (12.5 microg/dose); engraftment was similar to KL alone. At 8 months after transplantation the levels of engraftment in other tissues such as bone marrow, spleen, and thymus correlated well with erythroid engraftment to suggest that multipotent long-term repopulating stem cells had engrafted in these animals. There are concerns for the toxicity of total body irradiation (TBI)- or busulfan-based regimens in young recipients of syngeneic or transduced autologous marrow who are transplanted for correction of genetic disease. In these recipients complete donor engraftment may not be needed. The results with KL and 5-FU are encouraging for the further refinement of non-TBI, nonbusulfan techniques to achieve stable mixed chimerism.

The radiation dose-survival of various hematopoietic cell subsets in murine bone marrow (BM) was determined in the cobblestone area forming cell (CAFC) assay under conditions of single-, split-, and multiple-dose irradiation. A greater recovery in cell survival with decreasing dose per fraction, or increasing fraction number, was observed for primitive CAFC day-28 and day-35 than for CAFC day-6 and day-12 (colony-forming unit (CFU)-granulocyte macrophage and CFU-spleen day-12 equivalents). Linear quadratic (LQ) model analysis of CAFC survival data provided an estimate of the alpha/beta ratio that is an inverse index of the fractionation effect and is known to be lower for late than for acutely responding tissues. This analysis gave decreasing alpha/beta ratios with increasing primitiveness of the CAFC subset. These values were found to be comparatively low (about 4 Gy) for CAFC day-28 and day-35 and are in general agreement with previous studies on long-term repopulation in vivo. In contrast, alpha/beta ratios of CAFC day-6 and day-12 were relatively high (above 6 Gy) and are consistent with values obtained from acute marrow failure. Delayed harvesting of BM after a single dose of 6 Gy showed little evidence of proliferative repopulation over 1 week and hence the differential dose-sparing effect of fractionation among the CAFC subsets appears to be mostly attributable to the influence of sublethal damage repair. These results require a reevaluation of previous notions of marrow stem cell radiosensitivity and repair based on acute marrow lethality (LD50/30) or spleen colony (CFU-S) data, especially when applied to fractionated total body irradiation effects on long-term repopulating stem cells in a BM transplant setting.