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SF3B1 mutations frequently occur in cancer yet lack targeted therapies. Clinical trials of XPO1 inhibitors, selinexor and eltanexor, in high-risk myelodysplastic neoplasms (MDS) revealed responders were enriched with SF3B1 mutations. Given that XPO1 (Exportin-1) is a nuclear exporter responsible for the export of proteins and multiple RNA species, this led to the hypothesis that SF3B1-mutant cells are sensitive to XPO1 inhibition, potentially due to altered splicing. Subsequent RNA sequencing after XPO1 inhibition in SF3B1 wildtype and mutant cells showed increased nuclear retention of RNA transcripts and increased alternative splicing in the SF3B1 mutant cells particularly of genes that impact apoptotic pathways. To identify novel drug combinations that synergize with XPO1 inhibition, a forward genetic screen was performed with eltanexor treatment implicating anti-apoptotic targets BCL2 and BCLXL, which were validated by functional testing in vitro and in vivo. These targets were tested in vivo using Sf3b1K700Econditional knock-in mice, which showed that the combination of eltanexor and venetoclax (BCL2 inhibitor) had a preferential sensitivity for SF3B1 mutant cells without excessive toxicity. In this study, we unveil the mechanisms underlying sensitization to XPO1 inhibition in SF3B1-mutant MDS and preclinically rationalize the combination of eltanexor and venetoclax for high-risk MDS.

In this study, Caeiro et al. describe the relationship between H3K36me deficiency, like that observed with H3K36M mutations, and H3K27me3 distribution in head and neck squamous cell carcinoma. Increased H3K27me3 promotes genome instability and susceptibility to PARP1/2 inhibitors, highlighting the therapeutic potential of this strategy in targeting H3K36me-deficient cancers.

Ischemic stroke and cerebral amyloid angiopathy (CAA) pose significant challenges in an aging population, particularly in post-stroke recovery. Using the 5xFAD mouse model, we explore the relationship between CAA, ischemic stroke, and tissue recovery. We hypothesize that amyloid-beta accumulation worsens stroke outcomes by inducing blood-brain barrier (BBB) dysfunction, leading to impaired neurogenesis. Our findings show that CAA exacerbates stroke outcomes, with mice exhibiting constricted BBB microvessels, reduced cerebral blood flow, and impaired tissue recovery. Transcriptional analysis shows that endothelial cells and neural progenitor cells (NPCs) in the hippocampus exhibit differential gene expression in response to CAA and stroke, specifically targeting the phosphatidylinositol 3-kinase (PI3K) pathway. In vitroexperiments with human NPCs validate these findings, showing that disruption of the CXCL12-PIK3C2A-CREB3L2axis impairs neurogenesis. Notably, PI3K pathway activation restores neurogenesis, highlighting a potential therapeutic approach. These results suggest that CAA combined with stroke induces microvascular dysfunction and aberrant neurogenesis through this specific pathway.

The oncoprotein Smoothened (SMO), a Frizzled-class-G-protein-coupled receptor, is the central transducer of hedgehog (Hh) signaling. While canonical SMO signaling is best understood in the context of cilia, evidence suggests that SMO has other functions in cancer biology that are unrelated to canonical Hh signaling. Herein, we provided evidence that elevated levels of human SMO show a strong correlation with elevated levels of insulin-like growth factor 1 receptor (IGF1R) and reduced survival in diffuse large B-cell lymphoma (DLBCL). As an integral component of raft microdomains, SMO plays a fundamental role in maintaining the levels of IGF1R in lymphoma and breast cancer cells as well IGF1R-associated activation of protein kinase B (AKT). Silencing of SMOincreases lysosomal degradation and favors a localization of IGF1R to late endosomal compartments instead of early endosomal compartments from which much of the receptor would normally recycle. In addition, loss of SMO interferes with the lipid raft localization and retention of the remaining IGF1R and AKT, thereby disrupting the primary signaling context for IGF1R/AKT. This activity of SMO is independent of its canonical signaling and represents a novel and clinically relevant contribution to signaling by the highly oncogenic IGF1R/AKT signaling axis.

Metastatic outgrowth is supported by metabolic adaptations that may differ from the primary tumor of origin. However, it is unknown if such adaptations are therapeutically actionable. Here we report a novel aminopyridine compound that targets a unique Phosphogluconate Dehydrogenase (PGD)-dependent metabolic adaptation in distant metastases from pancreatic cancer patients. Compared to structurally similar analogs, 6-aminopicolamine (6AP) potently and selectively reversed PGD-dependent metastatic properties, including intrinsic tumorigenic capacity, excess glucose consumption, and global histone hyperacetylation. 6AP acted as a water-soluble prodrug that was converted into intracellular bioactive metabolites that inhibited PGD in vitro, and 6AP monotherapy demonstrated anti-metastatic efficacy with minimal toxicity in vivo. Collectively, these studies identify 6AP and possibly other 6-aminopyridines as well-tolerated prodrugs with selectivity for metastatic pancreatic cancers. If unique metabolic adaptations are a common feature of metastatic or otherwise aggressive human malignancies, then such dependencies could provide a largely untapped pool of druggable targets for patients with advanced cancers.

Resistance to cancer treatment remains a major clinical hurdle. Here, we demonstrate that the CoREST complex is a key determinant of endocrine resistance and ER+breast cancer plasticity. In endocrine-sensitive cells, CoREST is recruited to regulatory regions co-bound to ERα and FOXA1 to regulate the estrogen pathway. In contrast, during temporal reprogramming towards a resistant state, CoREST is recruited to AP-1 sites. In reprogrammed cells, CoREST favors chromatin opening, cJUN binding to chromatin, and gene activation by controlling SWI/SNF recruitment independently of the demethylase activity of the CoREST subunit LSD1. Genetic and pharmacological CoREST inhibition reduces tumorigenesis and metastasis of endocrine-sensitive and endocrine-resistant xenograft models. Consistently, CoREST controls a gene signature involved in invasiveness in clinical breast tumors resistant to endocrine therapies. Our studies reveal CoREST functions that are co-opted to drive cellular plasticity and resistance to endocrine therapies and tumorigenesis, thus establishing CoREST as a potential therapeutic target for the treatment of advanced breast cancer.

The oncoprotein Smoothened (SMO), a Frizzled-class-G-protein-coupled receptor, is the central transducer of hedgehog (Hh) signaling. While canonical SMO signaling is best understood in the context of cilia, evidence suggests that SMO has other functions in cancer biology that are unrelated to canonical Hh signaling. Herein, we provided evidence that elevated levels of human SMO show a strong correlation with elevated levels of insulin-like growth factor 1 receptor (IGF1R) and reduced survival in diffuse large B-cell lymphoma (DLBCL). As an integral component of raft microdomains, SMO plays a fundamental role in maintaining the levels of IGF1R in lymphoma and breast cancer cells as well IGF1R-associated activation of protein kinase B (AKT). Silencing of SMOincreases lysosomal degradation and favors a localization of IGF1R to late endosomal compartments instead of early endosomal compartments from which much of the receptor would normally recycle. In addition, loss of SMO interferes with the lipid raft localization and retention of the remaining IGF1R and AKT, thereby disrupting the primary signaling context for IGF1R/AKT. This activity of SMO is independent of its canonical signaling and represents a novel and clinically relevant contribution to signaling by the highly oncogenic IGF1R/AKT signaling axis.

Rational new strategies are needed to treat tumors resistant to kinase inhibitors. Mechanistic studies of resistance provide fertile ground for development of new approaches. Cancer drug addiction is a paradoxical resistance phenomenon, well-described in MEK-ERK-driven solid tumors, in which drug-target overexpression promotes resistance but a toxic overdose of signaling if the inhibitor is withdrawn. This can permit prolonged control of tumors through intermittent dosing. We and others showed previously that cancer drug addiction arises also in the hematologic malignancy ALK-positive anaplastic large-cell lymphoma (ALCL) resistant to ALK-specific tyrosine kinase inhibitors (TKIs). This is driven by the overexpression of the fusion kinase NPM1-ALK, but the mechanism by which ALK overactivity drives toxicity upon TKI withdrawal remained obscure. Here we reveal the mechanism of ALK-TKI addiction in ALCL. We interrogated the well-described mechanism of MEK/ERK pathway inhibitor addiction in solid tumors and found it does not apply to ALCL. Instead, phosphoproteomics and confirmatory functional studies revealed that the STAT1 overactivation is the key mechanism of ALK-TKI addiction in ALCL. The withdrawal of TKI from addicted tumors in vitro and in vivo leads to overwhelming phospho-STAT1 activation, turning on its tumor-suppressive gene-expression program and turning off STAT3’s oncogenic program. Moreover, a novel NPM1-ALK-positive ALCL PDX model showed a significant survival benefit from intermittent compared with continuous TKI dosing. In sum, we reveal for the first time the mechanism of cancer drug addiction in ALK-positive ALCL and the benefit of scheduled intermittent dosing in high-risk patient-derived tumors in vivo.

Multiple myeloma is the second most common hematologic malignancy with an annual incidence of 35,000 new cases every year in the U.S. Due to improved access to effective therapies, overall survival has improved from 1-3 years to over 10-20 years. However, there is not yet any available curative therapy for multiple myeloma and most patients will suffer from recurrent relapses, with an unmet clinical need for novel therapies. The interplay between the bone marrow microenvironment and malignant plasma cells is critically important to better understand pathogenesis of the disease, to predict response to therapy (in particular, immunotherapy), and to identify novel drug targets. Leveraging the power of computer vision, we are developing novel machine learning algorithms to label and characterize individual cells from digitalized H&E and CD138 stained plasma cells in bone marrow core biopsies. A total of 188 patients were included in this analysis: 157 with multiple myeloma, 6 with monoclonal gammopathy of undetermined significance, 17 with smoldering multiple myeloma, and 6 with primary amyloidosis. The deep learning framework to build our artificial intelligence (AI) models is implemented by Pytorch. Using the surface creation tool from the Imaris 10.0.1 software, we are able to measure pixel intensity, area, sphericity, and other cellular features that are then correlated with myeloma clinical outcomes as well as defined cytogenetic subtypes of multiple myeloma in 2-D. As a preliminary step in this project we analyzed the IMARIS software's ability to accurately determine the number of plasma cells compared with clinical standards through a linear regression plot with strong correlation (R 2=0.9). In addition, we rendered the 3-D microenvironment by combining more than 60 sequential formalin-fixed paraffin embedded (FFPE) tissue block bone marrow biopsy samples sliced at a thickness of 4 microns. Through utilizing the surface creation tool on the 2-D images within the 3-D model, we can show distance measurements between plasma cells and other features of the microenvironment such as adipocytes. This insight allows us to better understand and control the immune microenvironment through observing the various 2-D tissue slices within the 3-D model. Furthermore, we have assessed whether multiple myeloma digital images are able to detect translocation [t(11;14)] multiple myeloma subtype, which is present in 15% to 24% of patients, shown to predict treatment response to Bcl-2 inhibitor therapy (such as venetoclax). A small cohort (n=25) of patients with t(11;14) have been compared to non-t(11;14) cases using the machine learning model and preliminary data indicate that there is a correlation between digital images and multiple myeloma subtype. In the future, we anticipate our AI model will improve the accuracy of diagnostic methods while reducing costs and offering deeper translational insights that will predict drug response in vivo.

SF3B1mutations are the most frequent spliceosomal alterations across cancers, yet no successful therapy exists to target this pathway. Previous findings from a phase 2 clinical trial of the XPO1 inhibitor selinexor in patients with high-risk myelodysplastic syndrome (MDS) relapsed or refractory to hypomethylating agents (HMA) revealed increased activity in patients with SF3B1mutations. XPO1 (Exportin-1) is responsible for the nuclear export of over 200 proteins, but also plays a role in the transport of multiple RNA species, including small nuclear RNAs (snRNAs), ribosomal RNAs (rRNAs), and select messenger RNAs (mRNAs) out of the nucleus. Given the role of XPO1 in exporting snRNAs, which form the catalytic portion of the spliceosome, we hypothesized that XPO1 inhibition may preferentially affect SF3B1-mutant cells via altered splicing, and that SF3B1-mutant high-risk MDS patients would have a better response to rational targeted drug combinations with next generation XPO1 inhibitors.

Acute myeloid leukemia (AML) is generally an aggressive and lethal malignancy characterized by the accumulation of immature myeloid cells in the bone marrow and peripheral blood. We have previously shown the dependence of AML, but not normal hematopoiesis, on the presence of coactivator associated arginine methyltransferase 1 (CARM1), which suggests that targeting CARM1 could be useful in the treatment of AML. In preclinical studies, we and others have shown promising effects of CARM1 inhibitors on the growth of hematologic malignancies 1. In order to unearth a potential mechanism for the strong efficacy of CARM1 inhibition or knockdown (KD) in the AML1-ETO (AE+) driven AML mouse model, we employed the BioID system in an AE+ human cell line, SKNO-1, to identify novel substrates and interacting partners of CARM1 that could drive the pathogenesis of the disease. We identified over 500 interactors of CARM1, many of which are novel, including one particularly promising therapeutic target, bromodomain-containing protein 4 (BRD4).

TET2haploinsufficiency is a driving event in myeloid cancers and is associated with a worse prognosis in patients with acute myeloid leukemia (AML). Enhancing residual TET2 activity using vitamin C increases oxidized 5-methylcytosine (mC) formation and promotes active DNA demethylation via base excision repair (BER), which slows leukemia progression. We utilize genetic and compound library screening approaches to identify rational combination treatment strategies to improve use of vitamin C as an adjuvant therapy for AML. In addition to increasing the efficacy of several US Food and Drug Administration (FDA)-approved drugs, vitamin C treatment with poly-ADP-ribosyl polymerase inhibitors (PARPis) elicits a strong synergistic effect to block AML self-renewal in murine and human AML models. Vitamin-C-mediated TET activation combined with PARPis causes enrichment of chromatin-bound PARP1 at oxidized mCs and γH2AX accumulation during mid-S phase, leading to cell cycle stalling and differentiation. Given that most AML subtypes maintain residual TET2expression, vitamin C could elicit broad efficacy as a PARPi therapeutic adjuvant.

Chronic lymphocytic leukemia (CLL) is a common B-cell malignancy characterized by a highly variable course and outcome. The disease is believed to be driven by B-cell receptor (BCR) signals generated by external antigens and/or cell-autonomous BCR interactions, but direct in vivo evidence for this is still lacking. To further define the role of the BCR pathway in the development and progression of CLL, we evaluated the capacity of different types of antigen/BCR interactions to induce leukemia in the Eμ-TCL1 transgenic mouse model. We show that cell autonomous signaling capacity is a uniform characteristic of the leukemia-derived BCRs and represents a prerequisite for CLL development. Low-affinity BCR interactions with autoantigens generated during apoptosis are also positively selected, suggesting that they contribute to the pathogenesis of the disease. In contrast, high-affinity BCR interactions are not selected, regardless of antigen form or presentation. We also show that the capacity of the leukemic cells to respond to cognate antigen correlates inversely with time to leukemia development, suggesting that signals induced by external antigen increase the aggressiveness of the disease. Collectively, these findings provide in vivo evidence that the BCR pathway drives the development and can influence the clinical course of CLL.

Chronic lymphocytic leukemia (CLL) is a common B-cell malignancy characterized by a highly variable course and outcome. The disease is believed to be driven by B-cell receptor (BCR) signals generated by external antigens and/or cell-autonomous BCR interactions, but direct in vivo evidence for this is still lacking. To further define the role of the BCR pathway in the development and progression of CLL, we evaluated the capacity of different types of antigen/BCR interactions to induce leukemia in the Eβ-TCL1 transgenic mouse model. We show that cell autonomous signaling capacity is a uniform characteristic of the leukemia-derived BCRs and represents a prerequisite for CLL development. Low-affinity BCR interactions with autoantigens generated during apoptosis are also positively selected, suggesting that they contribute to the pathogenesis of the disease. In contrast, high-affinity BCR interactions are not selected, regardless of antigen form or presentation. We also show that the capacity of the leukemic cells to respond to cognate antigen correlates inversely with time to leukemia development, suggesting that signals induced by external antigen increase the aggressiveness of the disease. Collectively, these findings provide in vivo evidence that the BCR pathway drives the development and can influence the clinical course of CLL.

Allergic contact dermatitis (ACD) is triggered by an aberrant hyperinflammatory immune response to innocuous chemical compounds and ranks as the world’s most prevalent occupational skin condition. Although a variety of immune effector cells are activated during ACD, regulatory T (Treg) cells are crucial in controlling the resulting inflammation. Insulin-like growth factor-1 (IGF-1) regulates cell proliferation and differentiation and accelerates wound healing and regeneration in several organs including the skin. Recently IGF-1 has also been implicated in protection from autoimmune inflammation by expansion of Treg cells. Here, we demonstrate that ectopic expression of IGF-1 in mouse skin suppresses ACD in a Treg cell-specific manner, increasing the number of Foxp3+ Treg cells in the affected area and stimulating lymphocyte production of the anti-inflammatory cytokine interleukin 10. Similar therapeutic effects can be achieved with systemic or topical delivery of IGF-1, implicating this growth factor as a promising new therapeutic option for the treatment of ACD.

Insulin-like growth factor 1 (IGF-1) is an important regulator of growth, survival, and differentiation in many tissues. It is produced in several isoforms that differ in their N-terminal signal peptide and C-terminal extension peptide. The locally acting isoform of IGF-1 (mIGF-1) was previously shown to enhance the regeneration of both muscle and heart. In this study, we tested the therapeutic potential of mIGF-1 in the skin by generating a transgenic mouse model in which mIGF-1 expression is driven by the keratin 14 promoter. IGF-1 levels were unchanged in the sera of hemizygous K14/mIGF-1 transgenic animals whose growth was unaffected. A skin analysis of young animals revealed normal architecture and thickness as well as proper expression of differentiation and proliferation markers. No malignant tumors were formed. Normal homeostasis of the putative stem cell compartment was also maintained. Healing of full-thickness excisional wounds was accelerated because of increased proliferation and migration of keratinocytes, whereas inflammation, granulation tissue formation, and scarring were not obviously affected. In addition, mIGF-1 promoted late hair follicle morphogenesis and cycling. To our knowledge, this is the first work to characterize the simultaneous, stimulatory effect of IGF-1 delivery to keratinocytes on two types of regeneration processes within a single mouse model. Our analysis supports the use of mIGF-1 for skin and hair regeneration and describes a potential cell type-restricted action.

Hematopoietic stem cells (HSCs) exhibit epigenetic reprogramming and decline in function with aging, and these changes may be predisposing mechanisms for development of clonal hematopoiesis and myeloid malignancies. Our recent study characterizing the epigenetic and transcriptional landscape of young (18-30 years) and aged (65-75 years) human CD34 +CD38 -bone marrow (BM) cells identified Lamin-A/C (LMNA) as one of the most downregulated genes with aging (7.9-fold, p=1.9x10 -13). LMNAencodes the nuclear lamina protein Lamin-A/C and is mutated in the premature aging disorder Hutchinson-Gilford Progeria Syndrome.

Poly-ADP-ribose polymerase inhibitors (PARPi) are currently in clinical trial to determine their therapeutic efficacy for the treatment of acute myeloid leukemia (AML). We have shown that vitamin C (VitC), an essential micronutrient and co-factor of Ten-Eleven translocation (TET) proteins, enhances AML sensitivity to PARPi, potentially due to an increased dependency on base-excision repair (BER) enzymes needed to remove TET-catalyzed oxidized methylcytosine bases via active DNA demethylation. TET2is the most frequently mutated TETgene in patients with AML, and vitamin C treatment can mimic genetic restoration of TET2 function, leading to DNA demethylation, differentiation, and leukemia cell death. Whether vitamin C efficacy in combination with PARPi depends on the level of TET2functional alleles is not yet known and may stratify whether TET2wild-type or mutant patients should be targeted by vitamin C adjuvant therapy.

Aging causes a gradual decline in hematopoietic stem cell (HSC) function, which increases the risk for hematological malignancies. While much has been done in murine models, human HSC aging impairment is less understood. We recently showed that Krüppel-like transcription factor 6 (KLF6) is among the top downregulated genes during human HSC aging, which correlates with H3K27ac loss at several upstream putative enhancers. Moreover, loss of KLF6 in human CD34 +cells resulted in impaired in vitro differentiation, increased colony-forming potential and a transcriptional profile similar to that of aged CD34 +CD38 -cells. We hypothesized that age-acquired deregulation of KLF6may be a key player in age-related HSC dysfunction and sought to fully characterize this. Thus, we isolated CD34 +cells from young (<32 y.o) and aged (>65 y.o.) healthy donors and performed CRISPR-Cas9 genome editing and transcriptional activation of KLF6, respectively, followed by epigenetic and transcriptional reprogramming, in vivo hematopoietic reconstitution, and analysis of DNA damage, apoptosis, and reactive oxygen species (ROS) levels.

No relevant conflicts of interest to declare.

No relevant conflicts of interest to declare.

Neel: Northern Biologics, LTD: Current equity holder in publicly-traded company, Other: Co- Founder; SAB: Other: Co-Founder; Navire Pharma: Consultancy, Current equity holder in publicly-traded company; Jengu Therapeutics: Consultancy, Current equity holder in publicly-traded company, Other: Co-Founder; Arvinas, Inc: Consultancy, Current equity holder in publicly-traded company; Recursion Pharma: Current equity holder in publicly-traded company.

Tactical disruption of protein synthesis is an attractive therapeutic strategy, with the first-in-class eIF4A-targeting compound zotatifin in clinical evaluation for cancer and COVID-19. The full cellular impact and mechanisms of these potent molecules are undefined at a proteomic level. Here, we report mass spectrometry analysis of translational reprogramming by rocaglates, cap-dependent initiation disruptors that include zotatifin. We find effects to be far more complex than simple “translational inhibition” as currently defined. Translatome analysis by TMT-pSILAC (tandem mass tag-pulse stable isotope labeling with amino acids in cell culture mass spectrometry) reveals myriad upregulated proteins that drive hitherto unrecognized cytotoxic mechanisms, including GEF-H1-mediated anti-survival RHOA/JNK activation. Surprisingly, these responses are not replicated by eIF4A silencing, indicating a broader translational adaptation than currently understood. Translation machinery analysis by MATRIX (mass spectrometry analysis of active translation factors using ribosome density fractionation and isotopic labeling experiments) identifies rocaglate-specific dependence on specific translation factors including eEF1ε1 that drive translatome remodeling. Our proteome-level interrogation reveals that the complete cellular response to these historical “translation inhibitors” is mediated by comprehensive translational landscape remodeling.

To mount an effective immune response against infectious pathogens or tissue injury, hematopoietic stem cells (HSCs) increase their proliferation and production of myeloid cells, including macrophages, which destroy the pathogens and repair the damaged tissue. Proper resolution of inflammation is essential to restore hematopoietic homeostasis, as unrestrained inflammation can result in life-threatening pathologies such as sepsis, autoimmune disorders and cancer. The molecular mechanisms that control the resolution of inflammation, and how these contribute to disease phenotypes, are poorly understood.

Diffuse large B-cell lymphoma (DLBCL) comprises a third of non-Hodgkin lymphoma (NHL), with incidence steadily rising in what is already the most common hematologic malignancy. The backbone of potentially curative frontline chemoimmunotherapy combinations like R-CHOP is doxorubicin (Dox), still considered the most active anti-lymphoma agent. Relapsed or refractory (rel/ref) disease after frontline treatment carries persistently poor prognosis, even with recent advances in immunotherapy. Development and implementation of new therapeutic strategies remain urgent priorities to address unmet clinical needs in both high-risk previously untreated and rel/ref patients.

Background:Pre-clinical studies show that statins may improve the efficacy of chemoimmunotherapy in patients with DLBCL, through interference with cell membrane-initiated signaling pathways. Clinical retrospective studies, however, yield conflicting data, due to heterogeneous properties of statins, including potency and hydrophilicity.

No relevant conflicts of interest to declare.

Österborg: BeiGene: Research Funding; Janssen: Research Funding; Abbvie: Research Funding; Kancera AB: Research Funding; Gilead: Research Funding. Vega:National Cancer Institute, national Institutes of Health: Other: Grant Funding-R01CA222918.

Introduction:ALK+ anaplastic large cell lymphoma (ALCL) frequently carries the t(2;5) resulting in overexpression of NPM-ALK oncoprotein, which activates many oncogenic pathways. The Jab1 (c-Jun activation domain-binding protein-1), initially discovered as a c-Jun co-activator, represents the fifth component of an evolutionary highly conserved 8-subunit protein complex, named COP9 signalosome (CSN). The Jab1/Csn5 gene operates as an oncogene in cancer through multiple mechanisms including cell cycle control via the CDK inhibitor p27. Recent evidence suggests that Jab1/Csn5 is also involved in immune checkpoint regulation through PD-L1 stabilization by inhibition of PD-L1 proteasomal degradation. Recently, we reported that the protein levels of Jab1/Csn5 are the highest in ALCL as compared to other peripheral T-cell lymphomas (PTCL) and significantly correlate with PD-L1 levels in PTCLs (Drakos et al, HemaSphere 2019; (3):p596, EHA abstract). In this study, we hypothesized that NPM-ALK may regulate Jab1/Csn5 expression and thus contributes to cell proliferation as well as PD-L1/PD1 immune checkpoint regulation.

No relevant conflicts of interest to declare.

Vega: National Cancer Institute, national Institutes of Health: Other: Grant Funding-R01CA222918.

Doxorubicin (Dox) remains the most active drug against aggressive lymphomas, forming the backbone of multiple potentially curative frontline combination regimens. R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone), for example, cures diffuse large B-cell Lymphoma (DLBCL), the most common lymphoid malignancy in the United States, greater than 60% of the time. Patients with relapsed/refractory disease, however, have poor prognosis and require new options. Advances in nanotechnology provide new opportunities to widen therapeutic windows for existing drugs by enhancing delivery to tumor cells and limiting toxicities to non-malignant tissues. Carbon-Nitride Dots (CND) are novel nanocarriers we have developed that can be conjugated with a diverse range of molecules and have an established safe pharmacologic profile. Here, we sought CND-based enhancement of Dox's anti-lymphoma activities.

Constitutive PI3K/AKT activation is relevant to multiple aspects of tumor growth and survival in numerous cancers including diffuse large B cell lymphoma (DLBCL). For example, PTEN loss is one of the mechanisms leading to constitutive PI3K/AKT activation in a subset of DLBCL. Smoothened (SMO) is a seven transmembrane spanning and Frizzled-class G-protein coupled receptor that functions as a Hedgehog (Hh) signal transducer. SMO is overexpressed in DLBCL cell lines and tumors. While canonical Hh signaling culminates in the activation of GLI transcription factors and is best understood in the context of cilia, “noncanonical” Hh signaling does not involve GLI transcriptional activity and remains less well characterized. Here, we found that SMO is not only an integral component of lipid rafts but also plays an unexpected central role in the organization of raft microdomains (specialized glycolipid-enriched microdomains known to serve as a highly dynamic signaling platform for cell surface receptors and signaling proteins) and in the sorting of lipid raft-associated proteins.

With aging there is a gradual decline in normal HSC function, which is accompanied by an increased risk for the development of hematological malignancies. While a lot of work has been done in mice to understand this functional decline, less is known about human HSC biology with aging. We recently reported that KLF6, a Krüpper-like transcription factor, is one of the top genes downregulated with aging in human Lin-CD34+CD38-cells, and that this downregulation correlates with loss of H3K27ac at several KLF6upstream putative enhancer regions. Therefore, we hypothesized that age-acquired epigenetic deregulation at the KLF6locus resulting in loss of expression may be implicated in age-related HSC dysfunction and increased risk of malignant transformation. In order to test this, we isolated CD34+hematopoietic stem and progenitor cells (HSPCs) from healthy individuals and performed CRISPR-Cas9-based genome editing and transcriptional activation of the KLF6locus. KLF6-deficient cells were evaluated in terms of their function by colony-forming potential, in vitro differentiation, and hematopoietic reconstitution in immunocompromised mice.

No relevant conflicts of interest to declare.

No relevant conflicts of interest to declare.

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