A TNFR1-UBCH10 axis drives lung squamous cell carcinoma dedifferentiation and metastasis through a cell-autonomous signaling loop.

Tumor necrosis factor receptor 1 (TNFR1), encoded by TNFRSF1A, is a critical transducer of inflammatory pathways, but its physiological role in human cancer is not completely understood. Here, we observed high expression of TNFR1 in many human lung squamous cell carcinoma (SCCs) samples and in spontaneous lung SCCs derived from kinase-dead Ikkα knock-in (KA/KA) mice. Knocking out Tnfrf1a in KA/KA mice blocked lung SCC formation. When injected via tail vein, KALLU+ lung SCC cells that highly expressed TNFR1/TNF, Sox2, c-Myc, Twist1, Bcl2, and UBCH10, generated dedifferentiated spindle cell carcinomas with epithelial-mesenchymal transition markers in mouse lungs. In contrast, KALLU+ cells with silenced TNFR1 and KALLU- cells that expressed low levels of TNFR1 generated well-differentiated lung SCCs and were less tumorigenic and metastatic. We identified a downstream effector of TNFR1: oncogenic UBCH10, an E2 ubiquitin-conjugating enzyme with targets including Twist1, c-Myc, and Sox2, which enhanced SCC cell dedifferentiation. Furthermore, Tg-K5.TNFR1;KA/KA mice, which expressed transgenic TNFR1 in keratin 5-positve epithelial cells, developed more poorly differentiated and metastatic lung SCCs than those found in KA/KA mice. These findings demonstrate that an overexpressed TNFR1-UBCH10 axis advances lung carcinogenesis and metastasis through a dedifferentiation mechanism. Constituents in this pathway may contribute to the development of differentiation-related therapies for lung SCC.

IKKα-deficient lung adenocarcinomas generate an immunosuppressive microenvironment by overproducing Treg-inducing cytokines.

The tumor microenvironment (TME) provides potential targets for cancer therapy. However, how signals originating in cancer cells affect tumor-directed immunity is largely unknown. Deletions in the CHUK locus, coding for IκB kinase α (IKKα), correlate with reduced lung adenocarcinoma (ADC) patient survival and promote KrasG12D-initiated ADC development in mice, but it is unknown how reduced IKKα expression affects the TME. Here, we report that low IKKα expression in human and mouse lung ADC cells correlates with increased monocyte-derived macrophage and regulatory T cell (Treg) scores and elevated transcription of genes coding for macrophage-recruiting and Treg-inducing cytokines (CSF1, CCL22, TNF, and IL-23A). By stimulating recruitment of monocyte-derived macrophages from the bone marrow and enforcing a TNF/TNFR2/c-Rel signaling cascade that stimulates Treg generation, these cytokines promote lung ADC progression. Depletion of TNFR2, c-Rel, or TNF in CD4+ T cells or monocyte-derived macrophages dampens Treg generation and lung tumorigenesis. Treg depletion also attenuates carcinogenesis. In conclusion, reduced cancer cell IKKα activity enhances formation of a protumorigenic TME through a pathway whose constituents may serve as therapeutic targets for KRAS-initiated lung ADC.

A phase 2 trial of the somatostatin analog pasireotide to prevent GI toxicity and acute GVHD in allogeneic hematopoietic stem cell transplant.

BACKGROUND: Allogeneic hematopoietic stem cell transplantation (HCT) is an often curative intent treatment, however it is associated with significant gastrointestinal (GI) toxicity and treatment related mortality. Graft-versus-host disease is a significant contributor to transplant-related mortality. We performed a phase 2 trial of the somatostatin analog pasireotide to prevent gastrointestinal toxicity and GVHD after myeloablative allogeneic HCT. METHODS: Patients received 0.9mg pasireotide every 12 hours from the day prior to conditioning through day +4 after HCT (or a maximum of 14 days). The primary outcomes were grade 3-4 gastrointestinal toxicity through day 30 and acute GVHD. Secondary outcomes were chronic GVHD, overall survival and relapse free survival at one year. Stool and blood samples were collected from before and after HCT for analyses of stool microbiome, local inflammatory markers, and systemic inflammatory and metabolic markers. Results were compared with matched controls. RESULTS: Twenty-six patients received pasireotide and were compared to 52 matched contemporaneous controls using a 1-2 match. Grade 3-4 GI toxicity occurred in 21 (81%) patients who received pasireotide and 35 (67%) controls (p = 0.33). Acute GVHD occurred in 15 (58%) patients in the pasireotide group and 28 (54%) controls (p = 0.94). Chronic GVHD occurred in 16 patients in the pasireotide group (64%) versus 22 patients in the control group (42%) (p = 0.12). Overall survival at 1 year in the pasireotide group was 63% (95% CI: 47%,86%) versus 82% (95% CI: 72%, 93%) in controls (log-rank p = 0.006). Relapse-free survival rate at one year was 40% (95% CI: 25%, 65%) in the pasireotide group versus 78% (95% CI: 68%, 91%) in controls (log-rank p = 0.002). After controlling for the effect of relevant covariates, patients in the pasireotide group had attenuated post-HCT loss of microbial diversity. Analysis of systemic inflammatory markers and metabolomics demonstrated feasibility of such analyses in patients undergoing allogeneic HCT. Baseline level and pre-to-post transplant changes in several inflammatory markers (including MIP1a, MIP1b, TNFa, IL8Pro, and IL6) correlated with likelihood of survival. CONCLUSIONS: Pasireotide did not prevent gastrointestinal toxicity or acute GVHD compared to contemporaneous controls. Pasireotide was associated with numerically higher chronic GVHD and significantly decreased OS and RFS compared to contemporaneous controls. Pasireotide may provide a locally protective effect in the stool microbiome and in local inflammation as measured by stool calprotectin, stool beta-defensin, and stool diversity index.

C-CBL is required for inhibition of angiogenesis through modulating JAK2/STAT3 activity in ROP development.

PURPOSE: The incidence of retinopathy of prematurity (ROP) has increased continuously in recent years. However, the therapeutic effects of current treatments still remain undesired. This study aims to investigate the role of C-CBL in retinal angiogenesis in ROP and its potential as a therapeutic target. METHODS: Mouse retina microvascular endothelial cells (mRMECs) and induced experimental ROP/ oxygen-induced retinopathy (OIR) mice were employed to investigate the role of C-CBL in angiogenesis with combined molecular and cellular approaches, and histopathology methods. OIR mouse pups at postnatal day 12 (P12) were either injected intravitreally with adenovirus overexpressing c-Cbl or c-Cbl siRNA. Retinal neovascularization and avascular status were evaluated by retinal immunofluorescence (IF) staining, whole-mounts and hematoxylin and eosin (H&E) staining. RESULTS: C-CBL inhibits neovascularization by negatively regulating JAK2/STAT3/VEGF signaling axis in a ubiquitination-dependent manner. Knockdown of c-Cbl by siRNA reduced ubiquitin-mediated JAK2 degradation and increased levels of p-JAK2, p-STAT3, VEGF, and neovascularization in mRMECs, which can be reversed by JAK2 inhibitor treatment. While knockdown of c-Cbl significantly increased neovascular (NV) zone in the retinas, c-Cbl overexpression inhibited neovascularization in the retinal tissues in OIR mice. CONCLUSION: We found that C-CBL is required for anti-neovascularization process in ROP development by inhibiting JAK2/STAT3-dependent angiogenesis. Thus, our finding strongly suggest that C-CBL may be a potential novel therapeutic target for treating ROP.

A phase II study of reduced intensity double umbilical cord blood transplantation using fludarabine, melphalan, and low dose total body irradiation.

In this multicenter Phase 2 single arm study, we substituted low dose total body irradiation (TBI) for antithymocyte globulin (ATG) in a reduced intensity conditioning regimen with the intent to lower the risk for viral infections after double umbilical cord blood (UCB) transplantation. The conditioning regimen consisted of fludarabine (30 mg/m2/day, Day -7 to -2), melphalan (100 mg/m2/day, Day -1), and TBI (200cGy, Day 0). Graft-versus-host disease prophylaxis was sirolimus and tacrolimus. Thirty-one patients were treated on the protocol. The median time of follow-up for survivors was 24 months (range, 3.3-55.1). Nineteen patients experienced a total of 24 clinically significant viral reactivations or infections, with 1-year cumulative incidence rate of first significant viral event as 64% (95% CI, 43-79%), compared with our historical control of 53%. Within the context of these 24 clinically significant viral reactivations, there were a total of 10 infections with organ involvement. Nonrelapse mortality was 28% (95% CI 13-45%) at 2 years. The 2-year overall and progression-free survivals were 53% (95% CI 33-69%) and 47% (95% CI 28-64%), respectively. In conclusion, the substitution of low dose TBI for ATG did not decrease the incidence of significant viral events after UCB transplantation.

IKKα deficiency disrupts the development of marginal zone and follicular B cells.

Only few genes have been confidently identified to be involved in the Follicular (FO) and Marginal Zone (MZ) B cell differentiation, migration, and retention in the periphery. Our group previously observed that IKKα kinase inactive mutant mice IKKαK44A/K44A have significantly lower number of MZ B cells whereas FO B cell numbers appeared relatively normal. Because kinase dead IKKα can retain some of its biological functions that may interfere in revealing its actual role in the MZ and FO B cell differentiation. Therefore, in the current study, we genetically deleted IKKα from the pro-B cell lineage that revealed novel functions of IKKα in the MZ and FO B lymphocyte development. The loss of IKKα produces a significant decline in the percentage of immature B lymphocytes, mature marginal zone B cells, and follicular B cells along with a severe disruption of splenic architecture of marginal and follicular zones. IKKα deficiency affect the recirculation of mature B cells through bone marrow. A transplant of IKKα knockout fetal liver cells into Rag-/- mice shows a significant reduction compared to control in the B cells recirculating through bone marrow. To reveal the genes important in the B cell migration, a high throughput gene expression analysis was performed on the IKKα deficient recirculating mature B cells (B220+IgMhi). That revealed significant changes in the expression of genes involved in the B lymphocyte survival, homing and migration. And several among those genes identified belong to G protein family. Taken together, this study demonstrates that IKKα forms a vial axis controlling the genes involved in MZ and FO B cell differentiation and migration.

Macrophage inducible nitric oxide synthase circulates inflammation and promotes lung carcinogenesis.

Human lung squamous cell carcinoma (SCC) is highly associated with increased pulmonary macrophage infiltration. Previously, we showed that marked pulmonary infiltrating macrophages were required for spontaneous lung SCC development in a mouse model (L-IkkαKA/KA , KA/KA) that resembles human lung SCC. Interestingly the lung SCC-associated macrophages specifically express elevated inducible nitric oxide synthase (NOS2). However, the role of macrophage NOS2 in lung carcinogenesis has not been explored. Here, we show that NOS2 ablation inhibits macrophage infiltration, fibrosis, and SCC development in the lungs of KA/KA mice. Macrophage NOS2 was found to circulate inflammation and enhance macrophage migration and survival. NOS2 promotes foamy macrophage formation characterized with impaired lipid metabolism. NOS2 null bone marrow transplantation reduces foamy macrophage numbers and carcinogenesis in KA/KA chimaeras. This finding sheds light on a new mechanism by which macrophage NOS2 increases pulmonary inflammatory responses and macrophage survival and impairs macrophage lipid metabolism, thereby promoting lung SCC formation.

Phase I Trial of Brentuximab Vedotin for Steroid-Refractory Chronic Graft-versus-Host Disease after Allogeneic Hematopoietic Cell Transplantation.

We conducted a phase I study of brentuximab vedotin (BV), an antibody-drug conjugate targeting CD30, for the treatment of steroid-refractory chronic graft-versus-host disease (cGVHD). A modified 3 + 3 study design was used with the primary endpoint to determine the maximum tolerated dose of BV in this population. Escalating doses of BV were planned, starting with .6 mg/kg every 3 weeks (dose level 0) and increasing by .3 mg/kg per dose level. BV was administered in 21-day cycles for up to 16 cycles of therapy. Nineteen patients were enrolled on the study, with 2 withdrawing consent before dosing. The median number of cycles of therapy was 4 (range, 1 to 16). Reasons for stopping therapy prematurely included toxicities (n = 9), patient decision (n = 3), lack of response (n = 2), and death (n = 1). There were 2 dose-limiting toxicities observed: posterior reversible encephalopathy syndrome (cohort 4, grade 3) and sepsis (cohort 4, grade 4). The maximum tolerated dose was not reached because the trial was prematurely closed due to toxicity. Seven patients (41%) developed grade 3 or 4 adverse events that were attributed to therapy, including 4 patients who developed moderate or severe peripheral neuropathy that led to cessation of treatment in each case. According to National Institutes of Health cGVHD response criteria, 8 patients (47%) experienced a partial response, whereas 9 patients (53%) had a lack of response. There were no complete responses observed. Eleven patients (65%) were able to decrease their systemic corticosteroid dose by ≥50% by 6 months after initiation of BV, including 3 patients who were able to stop corticosteroids completely. The median soluble CD30 level before therapy was 61.5 ng/mL (range, 7.8 to 474.9); however, we did not observe any association between soluble CD30 level and cGVHD severity at enrollment or clinical responses to BV. In conclusion, BV may have activity in treatment of steroid-refractory cGVHD, yet its use is limited by treatment-emergent toxicities, including peripheral neuropathy. Continued efforts to investigate targeted approaches to cGVHD that do not cause broad immunosuppression are needed.

Third-party fecal microbiota transplantation following allo-HCT reconstitutes microbiome diversity.

We hypothesized that third-party fecal microbiota transplantation (FMT) may restore intestinal microbiome diversity after allogeneic hematopoietic cell transplantation (allo-HCT). In this open-label single-group pilot study, 18 subjects were enrolled before allo-HCT and planned to receive third-party FMT capsules. FMT capsules were administered no later than 4 weeks after neutrophil engraftment, and antibiotics were not allowed within 48 hours before FMT. Five patients did not receive FMT because of the development of early acute gastrointestinal (GI) graft-versus-host disease (GVHD) before FMT (n = 3), persistent HCT-associated GI toxicity (n = 1), or patient decision (n = 1). Thirteen patients received FMT at a median of 27 days (range, 19-45 days) after HCT. Participants were able to swallow and tolerate all FMT capsules, meeting the primary study endpoint of feasibility. FMT was tolerated well, with 1 treatment-related significant adverse event (abdominal pain). Two patients subsequently developed acute GI GVHD, with 1 patient also having concurrent bacteremia. No additional cases of bacteremia occurred. Median follow-up for survivors is 15 months (range, 13-20 months). The Kaplan-Meier estimates for 12-month overall survival and progression-free survival after FMT were 85% (95% confidence interval, 51%-96%) and 85% (95% confidence interval, 51%-96%), respectively. There was 1 nonrelapse death resulting from acute GI GVHD (12-month nonrelapse mortality, 8%; 95% confidence interval, 0%-30%). Analysis of stool composition and urine 3-indoxyl sulfate concentration indicated improvement in intestinal microbiome diversity after FMT that was associated with expansion of stool-donor taxa. These results indicate that empiric third-party FMT after allo-HCT appears to be feasible, safe, and associated with expansion of recipient microbiome diversity. This trial was registered at www.clinicaltrials.gov as #NCT02733744.

IKKα inactivation promotes Kras-initiated lung adenocarcinoma development through disrupting major redox regulatory pathways.

Lung adenocarcinoma (ADC) and squamous cell carcinoma (SCC) are two distinct and predominant types of human lung cancer. IκB kinase α (IKKα) has been shown to suppress lung SCC development, but its role in ADC is unknown. We found inactivating mutations and homologous or hemizygous deletions in the CHUK locus, which encodes IKKα, in human lung ADCs. The CHUK deletions significantly reduced the survival time of patients with lung ADCs harboring KRAS mutations. In mice, lung-specific Ikkα ablation (IkkαΔLu ) induces spontaneous ADCs and promotes KrasG12D-initiated ADC development, accompanied by increased cell proliferation, decreased cell senescence, and reactive oxygen species (ROS) accumulation. IKKα deletion up-regulates NOX2 and down-regulates NRF2, leading to ROS accumulation and blockade of cell senescence induction, which together accelerate ADC development. Pharmacologic inhibition of NADPH oxidase or ROS impairs KrasG12D-mediated ADC development in IkkαΔLu mice. Therefore, IKKα modulates lung ADC development by controlling redox regulatory pathways. This study demonstrates that IKKα functions as a suppressor of lung ADC in human and mice through a unique mechanism that regulates tumor cell-associated ROS metabolism.

Phase 1 multicenter trial of brentuximab vedotin for steroid-refractory acute graft-versus-host disease.

Therapy for steroid-refractory acute graft-versus-host disease (SR-aGVHD) remains suboptimal. Preclinical data demonstrate increased CD30 expression on activated CD8+ T cells during aGVHD. Brentuximab vedotin (BV) is an antibody-drug conjugate targeting CD30. We conducted a multicenter phase 1 trial in 34 patients to establish the maximum tolerated dose (MTD) of BV for SR-aGVHD treatment. A 3+3 cohort design was conducted initially with BV given weekly × 3 doses followed by maintenance dosing (initial dose 0.6 mg/kg IV weekly). Six patients were treated with the initial weekly dosing scheme; 2 of these patients died of neutropenic sepsis complications. The trial was subsequently revised to escalating cohorts of 5 patients treated every 2 weeks × 4 doses with a 4-week dose-limiting toxicity (DLT) period. Twenty-eight patients were treated with every-2-week dosing (n = 10 at 0.6 mg/kg; n = 18 at 0.8 mg/kg). MTD was defined at 0.8 mg/kg with 1 DLT observed (sepsis). At day 28, the overall response rate was 38.2% with 5 complete responses (CRs; 14.7%) and 8 very-good-partial responses (23.5%). An additional 7 patients achieved CR by day 56. With 12 months' follow-up on all patients, overall survival was 41% (95% confidence interval [CI], 25%-57%) at 6 months and 38% (95% CI, 22%-54%) at 12 months. CD30 expression on central memory CD8+, central memory CD4+, and regulatory T-lymphocyte subsets at enrollment was not associated with clinical response. BV is tolerable and has activity in SR-aGVHD and merits further investigation. This trial was registered at www.clinicaltrials.gov as #NCT01940796.

Autoreactive T Cells and Chronic Fungal Infection Drive Esophageal Carcinogenesis.

Humans with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED), a T cell-driven autoimmune disease caused by impaired central tolerance, are susceptible to chronic fungal infection and esophageal squamous cell carcinoma (ESCC). However, the relationship between autoreactive T cells and chronic fungal infection in ESCC development remains unclear. We find that kinase-dead Ikkα knockin mice develop APECED-like phenotypes, including impaired central tolerance, autoreactive T cells, chronic fungal infection, and ESCCs expressing specific human ESCC markers. Using this model, we investigated the link between ESCC and fungal infection. Autoreactive CD4 T cells permit fungal infection and incite tissue injury and inflammation. Antifungal treatment or autoreactive CD4 T cell depletion rescues, whereas oral fungal administration promotes, ESCC development. Inhibition of inflammation or epidermal growth factor receptor (EGFR) activity decreases fungal burden. Fungal infection is highly associated with ESCCs in non-autoimmune human patients. Therefore, autoreactive T cells and chronic fungal infection, fostered by inflammation and epithelial injury, promote ESCC development.

Phospholipid profiling identifies acyl chain elongation as a ubiquitous trait and potential target for the treatment of lung squamous cell carcinoma.

Lung cancer is the leading cause of cancer death. Beyond first line treatment, few therapeutic options are available, particularly for squamous cell carcinoma (SCC). Here, we have explored the phospholipidomes of 30 human SCCs and found that they almost invariably (in 96.7% of cases) contain phospholipids with longer acyl chains compared to matched normal tissues. This trait was confirmed using in situ 2D-imaging MS on tissue sections and by phospholipidomics of tumor and normal lung tissue of the L-IkkαKA/KA mouse model of lung SCC. In both human and mouse, the increase in acyl chain length in cancer tissue was accompanied by significant changes in the expression of acyl chain elongases (ELOVLs). Functional screening of differentially expressed ELOVLs by selective gene knockdown in SCC cell lines followed by phospholipidomics revealed ELOVL6 as the main elongation enzyme responsible for acyl chain elongation in cancer cells. Interestingly, inhibition of ELOVL6 drastically reduced colony formation of multiple SCC cell lines in vitro and significantly attenuated their growth as xenografts in vivo in mouse models. These findings identify acyl chain elongation as one of the most common traits of lung SCC discovered so far and pinpoint ELOVL6 as a novel potential target for cancer intervention.

Improving Human Immunodeficiency Virus/AIDS Palliative Care in Critical Care.

BACKGROUND: Critical care nurses provide palliative care to many patients; often, this includes the patient diagnosed with human immunodeficiency virus (HIV)/AIDS. Ongoing education about both palliative care and this complex diagnosis prepares the nurse to provide compassion and informed care. OBJECTIVES: This study examines the effects of an educational intervention addressing palliative care in the intensive care unit and the needs of the HIV/AIDS patients and families. The study will evaluate the critical care nurses' knowledge and competence in caring for this population following the educational sessions. METHODS: Thirty critical care nurses were recruited from the critical care unit at a hospital in the south. An HIV/AIDS palliative care course provided participants background knowledge, general principles, and opportunities for critical thinking regarding palliative care. A pretest and posttest on palliative care were provided to each subject to assess knowledge and confidence in palliative care in critical care nursing. RESULTS: The convenience sample of 30 nurses attained a mean pretest score of 82.9%. Their scores improved to 93.5% following the palliative care course. The nurses felt they improved in providing palliative care to patients and in taking responsibility for their practice. Ninety-three percent of the participants wanted to incorporate a palliative care course in nursing orientation. DISCUSSION: The course improved nurses' knowledge of palliative care for HIV/AIDS patients and their competency in palliative care. Thus, the palliative care course gave nurses deeper insight and improved their ability to provide competence palliative care.

IKKα negatively regulates ASC-dependent inflammasome activation.

The inflammasomes are multiprotein complexes that activate caspase-1 in response to infections and stress, resulting in the secretion of pro-inflammatory cytokines. Here we report that IκB kinase α (IKKα) is a critical negative regulator of apoptosis-associated specklike protein containing a C-terminal caspase-activation-andrecruitment (CARD) domain (ASC)-dependent inflammasomes. IKKα controls the inflammasome at the level of the adaptor ASC, which interacts with IKKα in the nucleus of resting macrophages in an IKKα kinase-dependent manner. Loss of IKKα kinase activity results in inflammasome hyperactivation. Mechanistically, the downstream nuclear effector IKK-related kinase (IKKi) facilitates translocation of ASC from the nucleus to the perinuclear area during inflammasome activation. ASC remains under the control of IKKα in the perinuclear area following translocation of the ASC/IKKα complex. Signal 2 of NLRP3 activation leads to inhibition of IKKα kinase activity through the recruitment of PP2A, allowing ASC to participate in NLRP3 inflammasome assembly. Taken together, these findings reveal a IKKi-IKKα-ASC axis that serves as a common regulatory mechanism for ASC-dependent inflammasomes.

An IKKα-nucleophosmin axis utilizes inflammatory signaling to promote genome integrity.

The inflammatory microenvironment promotes skin tumorigenesis. However, the mechanisms by which cells protect themselves from inflammatory signals are unknown. Downregulation of IKKα promotes skin tumor progression from papillomas to squamous cell carcinomas, which is frequently accompanied by genomic instability, including aneuploid chromosomes and extra centrosomes. In this study, we found that IKKα promoted oligomerization of nucleophosmin (NPM), a negative centrosome duplication regulator, which further enhanced NPM and centrosome association, inhibited centrosome amplification, and maintained genome integrity. Levels of NPM hexamers and IKKα were conversely associated with skin tumor progression. Importantly, proinflammatory cytokine-induced IKKα activation promoted the formation of NPM oligomers and reduced centrosome numbers in mouse and human cells, whereas kinase-dead IKKα blocked this connection. Therefore, our findings suggest a mechanism in which an IKKα-NPM axis may use inflammatory signals to suppress centrosome amplification, promote genomic integrity, and prevent tumor progression.

The pivotal role of IKKα in the development of spontaneous lung squamous cell carcinomas.

Here, we report that kinase-dead IKKα knockin mice develop spontaneous lung squamous cell carcinomas (SCCs) associated with IKKα downregulation and marked pulmonary inflammation. IKKα reduction upregulated the expression of p63, Trim29, and keratin 5 (K5), which serve as diagnostic markers for human lung SCCs. IKKα(low)K5(+)p63(hi) cell expansion and SCC formation were accompanied by inflammation-associated deregulation of oncogenes, tumor suppressors, and stem cell regulators. Reintroducing transgenic K5.IKKα, depleting macrophages, and reconstituting irradiated mutant animals with wild-type bone marrow (BM) prevented SCC development, suggesting that BM-derived IKKα mutant macrophages promote the transition of IKKα(low)K5(+)p63(hi) cells to tumor cells. This mouse model resembles human lung SCCs, sheds light on the mechanisms underlying lung malignancy development, and identifies targets for therapy of lung SCCs.

IKKα-mediated signaling circuitry regulates early B lymphopoiesis during hematopoiesis.

Multiple transcription factors regulate B-cell commitment, which is coordinated with myeloid-erythroid lineage differentiation. NF-κB has long been speculated to regulate early B-cell development; however, this issue remains controversial. IκB kinase-α (IKKα) is required for splenic B-cell maturation but not for BM B-cell development. In the present study, we unexpectedly found defective BM B-cell development and increased myeloid-erythroid lineages in kinase-dead IKKα (KA/KA) knock-in mice. Markedly increased cytosolic p100, an NF-κB2-inhibitory form, and reduced nuclear NF-κB p65, RelB, p50, and p52, and IKKα were observed in KA/KA splenic and BM B cells. Several B- and myeloid-erythroid-cell regulators, including Pax5, were deregulated in KA/KA BM B cells. Using fetal liver and BM congenic transplantations and deleting IKKα from early hematopoietic cells in mice, this defect was identified as being B cell-intrinsic and an early event during hematopoiesis. Reintroducing IKKα, Pax5, or combined NF-κB molecules promoted B-cell development but repressed myeloid-erythroid cell differentiation in KA/KA BM B cells. The results of the present study demonstrate that IKKα regulates B-lineage commitment via combined canonical and noncanonical NF-κB transcriptional activities to target Pax5 expression during hematopoiesis.