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Supplementary Figure 1. Hypoxia regulates WM cell formation of clumps in an E-cadherin-dependent manner. The effect of E-cadherin blocking antibody (5 μg/mL) on the size of colonies created by BCWM.1 cells in normoxia or hypoxia normalized to normoxic untreated cells (A); and on the colony formation by BCWM.1 cells as shown by representative pictures (scale bar represents 1 micrometer) (B).

Supplementary Figure 2. Re-oxygenation induces WM cell clump-formation. The effect of hypoxia (1% O2, 48hrs) and re-oxygenation (hypoxia for 24hrs followed by normoxia for 24hrs) on BCWM.1 size of colonies normalized to hypoxic cells (A), and on the creation of clumps monitored and captured using light microscopy (scale bar represents 1 micrometer) (B).

Chronic myeloid leukemia (CML), acute myeloid leukemia (AML), and chronic lymphocytic leukemia (CLL) are hematological malignancies that remain incurable despite novel treatments. In order to improve current treatments and clinical efficacy, there remains a need for more complex

Micrograph comparison remains useful in bioscience. This technology provides researchers with a quick snapshot of experimental conditions. But sometimes a two- condition comparison relies on researchers' eyes to draw conclusions. Our Bioimage Analysis, Statistic, and Comparison (BASIN) software provides an objective and reproducible comparison leveraging inferential statistics to bridge image data with other modalities. Users have access to machine learning-based object segmentation. BASIN provides several data points such as images' object counts, intensities, and areas. Hypothesis testing may also be performed. To improve BASIN's accessibility, we implemented it using R Shiny and provided both an online and offline version. We used BASIN to process 498 image pairs involving five bioscience topics. Our framework supported either direct claims or extrapolations 57% of the time. Analysis results were manually curated to determine BASIN's accuracy which was shown to be 78%. Additionally, each BASIN version's initial release shows an average 82% FAIR compliance score.

This study investigates the effects of a dual selective Class I histone deacetylase (HDAC)/lysine-specific histone demethylase 1A (LSD1) inhibitor known as 4SC-202 (Domatinostat) on tumor growth and metastasis in a highly metastatic murine model of Triple Negative Breast Cancer (TNBC). 4SC-202 is cytotoxic and cytostatic to the TNBC murine cell line 4T1 and the human TNBC cell line MDA-MB-231; the drug does not kill the normal breast epithelial cell line MCF10A. Furthermore, 4SC-202 reduces cancer cell migration. In vivo studies conducted in the syngeneic 4T1 model, which closely mimics human TNBC in terms of sites of metastasis, reveal reduced tumor burden and lung metastasis. The mechanism of action of 4SC-202 may involve effects on cancer stem cells (CSC) which can self-renew and form metastatic lesions. Approximately 5% of the total 4T1 cell population grown in three-dimensional scaffolds had a distinct CD44high/CD24low CSC profile which decreased after treatment. Bulk transcriptome (RNA) sequencing analyses of 4T1 tumors reveal changes in metastasis-related pathways in 4SC-202-treated tumors, including changes to expression levels of genes implicated in cell migration and cell motility. In summary, 4SC-202 treatment of tumors from a highly metastatic murine model of TNBC reduces metastasis and warrants further preclinical studies.

*denotes Co-First Authorship SuppFile1_MethodsandFigures.docx:Supplementary File 1 Methods and Figures;Full bioinformatics methods and supplementary figures.,SuppFile2_DAVID_4SCvsControl_70DEGs.xlsx;DAVID Annotation 4SC-202 vs Control 70 DEGs:Full functional annotation clustering results from DAVID Bioinformatics Resource for the4SC-202-induced, consensus differentially expressed genes., SuppFile3_DAVID_4SCvsVori_33DEGs.xlsx;DAVID Annotation 4SC-202 vs Control 33 DEGs:Full functional annotation clustering results from DAVID Bioinformatics Resource for the 4SC-202versus Vorinostat consensus differentially expressed genes., SuppFile4_IPA_70_Enrichment_Cannonical_pathways.xls;IPA Canonical Pathways Enrichment 70 DEGs:Full Ingenuity Pathway Analysis (IPA) canonical pathways enrichment results for the4SC-202-induced, consensus differentially expressed genes.,SuppFile5_IPA_33_Summary.pdf;Supplementary File 5 - IPA Summary of 4SC-202 vs Vorinostat 33 DEGs:Ingenuity Pathway Analysis (IPA) summary of the enrichment results for the4SC-202-induced, consensus differentially expressed genes against Vorinostat.,SuppFile6_ExperimentRINNumbers.pdf;Supplementary File 6 - RNA Integrity Numbers:RNA extraction quality control step, one of the various steps of quality control within the RNA-sequencing workflow. These RNA Integrity numbers are from the Agilent 2100 Bioanalyzer that looks for RNA contamination and degradation.,SuppFile7_4SCvsControl_allDEGs.xlsx;Workflow results including all DEGs for 4SC-202 vs Control:Full excel file that contains all of the DEGs from the results of all workflows for 4SC-202.

Lack of efficacy and a low overall success rate of phase I-II clinical trials are the most common failures when it comes to advancing cancer treatment. Current drug sensitivity screenings present several challenges including differences in cell growth rates, the inconsistent use of drug metrics, and the lack of translatability. Here, we present a patient-derived 3D culture model to overcome these limitations in breast cancer (BCa). The human plasma-derived 3D culture model (HuP3D) utilizes patient plasma as the matrix, where BCa cell lines and primary BCa biopsies were grown and screened for drug treatments. Several drug metrics were evaluated from relative cell count and growth rate curves. Correlations between HuP3D metrics, established preclinical models, and clinical effective concentrations in patients were determined. HuP3D efficiently supported the growth and expansion of BCa cell lines and primary breast cancer tumors as both organoids and single cells. Significant and strong correlations between clinical effective concentrations in patients were found for eight out of ten metrics for HuP3D, while a very poor positive correlation and a moderate correlation was found for 2D models and other 3D models, respectively. HuP3D is a feasible and efficacious platform for supporting the growth and expansion of BCa, allowing high-throughput drug screening and predicting clinically effective therapies better than current preclinical models., Institutional Development Award (IDeA) from the National Institute of General Medical Sciences of the National Institutes of Health 5P20GM103548, 2018 LUSH Prize (Young Investigator Award)

Central nervous system atypical teratoid/rhabdoid tumors (ATRTs) are rare and aggressive tumors with a very poor prognosis. Current treatments for ATRT include resection of the tumor, followed by systemic chemotherapy and radiation therapy, which have toxic side effects for young children. Gene expression analyses of human ATRTs and normal brain samples indicate that ATRTs have aberrant expression of epigenetic markers including class I histone deacetylases (HDAC&rsquo, s) and lysine demethylase (LSD1). Here, we investigate the effect of a small molecule epigenetic modulator known as Domatinostat (4SC-202), which inhibits both class I HDAC&rsquo, s and Lysine Demethylase (LSD1), on ATRT cell survival and single cell heterogeneity. Our findings suggest that 4SC-202 is both cytotoxic and cytostatic to ATRT in 2D and 3D scaffold cell culture models and may target cancer stem cells. Single-cell RNA sequencing data from ATRT-06 spheroids treated with 4SC-202 have a reduced population of cells overexpressing stem cell-related genes, including SOX2. Flow cytometry and immunofluorescence on 3D ATRT-06 scaffold models support these results suggesting that 4SC-202 reduces expression of cancer stem cell markers SOX2, CD133, and FOXM1. Drug-induced changes to the systems biology landscape are also explored by multi-omics enrichment analyses. In summary, our data indicate that 4SC-202 has both cytotoxic and cytostatic effects on ATRT, targets specific cell sub-populations, including those with cancer stem-like features, and is an important potential cancer therapeutic to be investigated in vivo.

Introduction: Multiple myeloma (MM) is the cancer of plasma cells within the bone marrow (BM) and represents the second most common hematologic malignancy. Although therapeutic options have broadened over the years, the disease is challenged by frequent relapses. Relapsed/refractory MM (RRMM) often becomes non-responsive to previous lines of treatment and has significantly poorer survival outcome. Physicians are faced with a difficult task to choose a right treatment regimen. Thus, a precision medicine tool that predicts the clinical response of individual patients to therapy is greatly desired. We have previously developed a novel 3D tissue-engineered BM (3DTEBM) culture model, which is patient derived, closely recapitulates the pathophysiological conditions in the BM, and allows ex vivo proliferation of primary cells of various hematologic malignancies. In this study, we conducted a retrospective study that tests the ability of the ex vivo 3DTEBM platform to predict the clinical response in individual MM patients, to help decision-making process for RRMM. We hypothesized that the 3DTEBM will be able to predict clinical responses of RRMM patients. Methods: We first performed a literature search to examine the clinical efficacious concentrations (Css) for 10 MM drugs. We then experimentally determined the in vitro efficacious concentrations (IC50) of these drugs in MM cell lines, in both 2D and 3DTEBM cultures. The IC50 values were then correlated with their respective clinical Css values to evaluate how well each culture system reproduce drug efficacy. For the retrospective trial, we used viably frozen whole BM samples from 19 RRMM patients with known clinical responsiveness to the regimen they received. 3DTEBM cultures were developed for each patient with BM biopsies obtained prior to the start of clinical regimen. Cultures were treated ex vivo with the same treatment regimen each patient received clinically, at increasing concentrations (0X, 3X and 10X of Css of individual drugs). After 4 days, cultures were digested and cells were retrieved for flow cytometry analysis. Primary cells were stained Leukocyte-/CD38+ and counted against counting beads. Survival was determined as % of untreated control, and ex vivo responsiveness was analyzed by ANOVA. Finally, the clinical team correlated the ex vivo response with the clinical response for each patient. Results: To demonstrate this discrepancy between drug efficacy in laboratory settings and clinical outcomes, we compared the in vitro IC50 to the clinical Css of 10 drugs used for the treatment of MM. We found that there was no correlation between the IC50 in classic 2D culture systems and the clinical Css (R 2=0.019) (Figure 1A). In contrast, the IC50 in the 3DTEBM directly correlated with the clinical Css (R 2=0.993) (Figure 1B). We then conducted a retrospective clinical trial to determine if the 3DTEBM platform is able to predict each patient's clinical response by recreating the same treatment regimen ex vivo (Figure 1C). The 3DTEBM was able to predict the response in 89% of the MM patient cohort across multiple treatment regimens, with no false positives (Figure 1D). Conclusions: Our retrospective clinical trial demonstrated that the 3DTEBM technology is a feasible platform for predicting therapeutic responses in MM with a high predictive accuracy within a clinically actionable time frame. Such platforms can provide precise clinical insight about the efficacy of different treatment plans and assist physicians to propose the best choice of therapy for their individual patients. Future prospective studies are needed to validate these significant findings by testing prospective prediction ability of 3DTEBM to improve therapy response in hematologic malignancies. Figure 1 Figure 1. Disclosures De La Puente: Cellatrix LLC: Other: Co-founder. Azab: Cellatrix LLC: Current Employment. Vij: BMS: Research Funding; Takeda: Honoraria, Research Funding; Sanofi: Honoraria, Research Funding; BMS: Honoraria; GSK: Honoraria; Oncopeptides: Honoraria; Karyopharm: Honoraria; CareDx: Honoraria; Legend: Honoraria; Biegene: Honoraria; Adaptive: Honoraria; Harpoon: Honoraria. Azab: Cellatrix, LLC: Current Employment, Current holder of individual stocks in a privately-held company.

Multiple myeloma (MM) presents a poor prognosis and high lethality of patients due to development of drug resistance. P-glycoprotein (P-gp), a drug-efflux transporter, is upregulated in MM patients post-chemotherapy and is involved in the development of drug resistance since many anti-myeloma drugs (including proteasome inhibitors) are P-gp substrates. Hypoxia develops in the bone marrow niche during MM progression and has long been linked to chemoresistance. Additionally, hypoxia-inducible transcription factor (HIF-1α) was demonstrated to directly regulate P-gp expression. We found that in MM patients P-gp expression positively correlated with the hypoxic marker, HIF-1α. Hypoxia increased P-gp protein expression and its efflux capabilities in MM cells in vitro using flow cytometry. We reported herein that hypoxia-mediated resistance to carfilzomib and bortezomib in MM cells is due to P-gp activity and was reversed by tariquidar, a P-gp inhibitor. These results suggest combining proteasome inhibitors with P-gp inhibition for future clinical studies.

Dexamethasone (dex) induces apoptosis in multiple myeloma (MM) cells and is a frontline treatment for this disease. However resistance to dex remains a major challenge and novel treatment approaches are needed. We hypothesized that dex utilizes translational pathways to promote apoptosis in MM and that specific targeting of these pathways could overcome dex-resistance. Global unbiased profiling of mRNA translational profiles in MM cells treated with or without dex revealed that dex significantly repressed eIF2 signaling, an important pathway for regulating ternary complex formation and protein synthesis. We demonstrate that dex induces the phosphorylation of eIF2α resulting in the translational upregulation of ATF4, a known eIF2 regulated mRNA. Pharmacologic induction of eIF2α phosphorylation via activation of the heme-regulated eIF2α kinase (HRI) induced apoptosis in MM cell lines and in primary MM cells from patients with dex-resistant disease. In addition, co-culture with marrow stroma failed to protect MM cells from apoptosis induced by targeting the eIF2 pathway. Combination therapy with rapamycin, an mTOR inhibitor, and BTdCPU, an activator of HRI, demonstrated additive effects on apoptosis in dex-resistant cells. Thus, specific activation of the eIF2α kinase HRI is a novel therapeutic target in MM that can augment current treatment strategies.

Multiple myeloma (MM) is a hematological malignancy that remains incurable, with relapse rates >90%. The main limiting factor for the effective use of chemotherapies in MM is the serious side effects caused by these drugs. The emphasis in cancer treatment has shifted from cytotoxic, non-specific chemotherapies to molecularly targeted and rationally designed therapies showing greater efficacy and fewer side effects. Traditional chemotherapy has shown several disadvantages such as lack of targeting capabilities, systemic toxicity, and side effects; low therapeutic index, as well as most anticancer drugs, has poor water solubility. Nanoparticle delivery systems (NPs) are capable of targeting large doses of chemotherapies into the target area while sparing healthy tissues, overcoming the limitations of traditional chemotherapy. Here, we review the current state of the art in nanoparticle-based strategies designed to treat MM. Many nanoparticle delivery systems have been studied for myeloma using non-targeted NPs (liposomes, polymeric NPs, and inorganic NPs), triggered NPs, as well as targeted NPs (VLA-4, ABC drug transporters, bone microenvironment targeting). The results in preclinical and clinical studies are promising; however, there remains much to be learned in the emerging field of nanomedicine in myeloma.

Oxygen deprivation within tumors is one of the most prevalent causes of resilient cancer cell survival and increased immune evasion in breast cancer (BCa). Current in vitro models do not adequately mimic physiological oxygen levels relevant to breast tissue and its tumor-immune interactions. Here, we propose an approach to engineer a three-dimensional (3D) model (named 3D engineered oxygen, 3D-O) that supports growth of BCa cells and generates physio- and pathophysiological oxygen levels. Low oxygen-induced changes within the 3D-O model supported known tumor hypoxia characteristics such as reduced BCa cell proliferation, increased extracellular matrix protein expression, increased extracellular vesicle secretion and enhanced immune surface marker expression on BCa cells. We further demonstrated that low oxygen-induced changes mimicked tumor-immune interactions leading to immune evasion mechanisms. CD8+ T cell infiltration was significantly impaired under pathophysiological oxygen levels and we were able to establish that hypoxia inhibition re-sensitize BCa cells to cytotoxic CD8+ T cells. Therefore, our novel 3D-O model could serve as a promising platform for the evaluation of immunological events and as a drug-screening platform tool to overcome hypoxia-driven immune evasion.

Boron neutron capture therapy (BNCT) has the potential to become a viable cancer treatment modality, but its clinical translation requires sufficient tumor boron delivery while minimizing nonspecific accumulation. Thermal sensitive liposomes (TSLs) were designed to have a stable drug payload at physiological temperatures but engineered to have high permeability under mild hyperthermia. We found that TSLs improved the tumor-specific delivery of boronophenylalanine (BPA) and boronated 2-nitroimidazole derivative B-381 in D54 glioma cells. Uniquely, the 2-nitroimidazole moiety extended the tumor retention of boron content compared to BPA. This is the first study to show the delivery of boronated compounds using TSLs for BNCT, and these results will provide the basis of future clinical trials using TSLs for BNCT.

El objetivo central de este estudio consiste en la aplicacion de las tecnicas de la ingenieria tisular en la profilaxis de la fistula broncopleural, patologia pulmonar con una mortalidad asociada del 33?3% y cuyos tratamientos actuales incluyen procedimientos quirurgicos agresivos. La utilizacion de andamiajes de fibrina autologos, elaborados a partir de la sangre del propio paciente, y cultivados con celulas autologas de la dermis y factores de crecimiento, se presenta como una tecnica novedosa y prometedora en diferentes aplicaciones clinicas de la ingenieria tisular y la medicina regenerativa. Los andamiajes de fibrina autologa son biocompatibles, con estructura porosa, donde las celulas son capaces de adherir, proliferar y diferenciar. La baja concentracion de fibrinogeno permite una optima proliferacion celular dentro de dicha estructura tridimensional, ademas de trabajar con una tecnica de elaboracion mas sencilla y barata que la de las fibrinas comerciales. Las celulas de la dermis del cerdo han resultado ser una fuente celular facilmente accesible, abundante y con una capacidad proliferativa adecuada, que las presenta como una alternativa muy interesante de celulas madre mesenquimales. Con la aplicacion combinada de celulas de la dermis y los factores de crecimiento VEGF y bFGF en el interior de andamiajes de fibrina, en un modelo porcino in vivo de neumonectomia, se ha conseguido una adecuada cicatrizacion del margen bronquial, junto con una evidente revascularizacion de la zona. Los buenos resultados obtenidos en cicatrizacion y formacion de una red capilar madura a partir de un injerto totalmente avascular, abre las puertas de su utilizacion en el tratamiento de patologias en las que la revascularizacion sea clave para la resolucion del proceso.

Despite significant improvements in research and development in the cancer field, about 95% of oncology drugs in clinical trials fail to receive FDA approval. Compelling evidence suggests that three-dimensional (3D) cell culture techniques provide useful advantages for modeling drug sensitivity; however, there are still challenges, including vast differences in cell growth rates, inconsistent use of drug metrics across different cellular platforms, costly and relatively time-consuming approaches, and findings that may not translate to humans due to the incorporation of non-native environments. A biochemically characterized human blood plasma matrix is used as the framework upon which the human-derived plasma 3D culture (huP3D) exists. Breast cancer (BCa) cell lines representing different molecular subtypes (MCF7, ZR-75-1, MDA-MB-453, SK-BR-3, and MDA-MB-231) were screened for commonly used chemotherapies (capecitabine, carboplatin, paclitaxel, docetaxel, epirubicin, methotrexate, and cyclophosphamide) in 2D and huP3D models after 7 days of treatment by flow cytometry. Relevant drug metrics for half maximal concentrations of inhibition (IC50), response (EC50), proliferation inhibition (GI50), and growth rate inhibition (GR50) were calculated. Literature searches of phase I/II studies for the clinical effective drug concentration (steady state concentration, Css) of the same chemotherapeutic drugs on patients, and preclinical IC50 on 2D or other 3D models, were performed to determine the ability of 2D, other 3D, and huP3D cultures to predict clinical efficacy. BCa cell lines in huP3D were able to synthetize relevant tumor microenvironment components including extracellular matrix proteins (collagens, laminin, and fibronectin), extracellular vesicles, and cytokines. Moderate (paclitaxel, capecitabine, methotrexate, cyclophosphamide) to strong (epirubicin, docetaxel, carboplatin) effects on BCa cell survival were found in 2D cultures, in addition to a heterogeneous response to the chemotherapeutic drugs in the BCa cell lines tested, with ZR-75-1 being the most resistant to the different drugs. 2D effective drug concentrations did not correlate with the literature search Css on patients (R2=0.05). On the contrary, BCa cells cultured in huP3D showed increased drug resistance to all the chemotherapeutic drugs and a better correlation with the clinical data than 2D and other 3D models. In particular, the GR50 drug metric showed the strongest correlation with clinical Css values (R2=0.87). Our results showed the feasibility and efficacy of the huP3D drug response metrics to predict clinically effective therapies better than current preclinical models. Our model presents a reproducible, human-derived, high-throughput in vitro 3D tissue culture system for modeling drug sensitivity and clinical efficacy. A critical value of the model would be to focus on the development of more personalized models using cells and plasma components from the same patient. Citation Format: Kristin Calar, Simona Plesselova, Somshuvra Bhattacharya, Pilar de la Puente. Feasibility and efficacy of a human-derived plasma 3D culture (huP3D) model to predict clinically effective drug treatment concentrations [abstract]. In: Proceedings of the AACR Special Conference on the Evolving Landscape of Cancer Modeling; 2020 Mar 2-5; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2020;80(11 Suppl):Abstract nr A22.

Introduction: Oxygen deprivation within tumors has been associated with enhanced cancer cell survival, altered extracellular matrix (ECM) production, and increased immune evasion in breast cancer (BCa). These outcomes collectively contribute to chemotherapeutic challenges. Current models do not adequately mimic physiologic oxygen levels relevant to breast tissue and tumor-immune interactions. Taking this into consideration, we developed a plasma-derived three-dimensional (3D) model that supports growth of BCa cells, generates physio- and pathophysiologic oxygen levels, and supports prevailing hypoxia-driven tumor outcomes such as immune evasion. Methods: BCa cells (MCF7 and MDA-MB-231) were embedded into 3D scaffolds formed through the cross-linking of patient-derived plasma. The oxygen content within these 3D matrices was engineered and further characterized to recapitulate physiologic blood and breast tissue (3D physiologic, gradient 14-10 kPa) or pathophysiologic (3D tumorous, gradient 9.6-2.4 kPa) levels by the manipulation of height, culture time, oxygen incubation environment, and cellular concentration. BCa cells grown within 3D physiologic and tumorous scaffolds were analyzed by flow cytometry, confocal imaging, or immunohistochemistry for the expression of hypoxia-inducible factor-1 alpha (HIF-1 alpha), proliferation capabilities, and ECM production. Peripheral blood mononuclear cells were incorporated on the top of 3D physiologic and tumorous scaffolds, and the differences in the tumor-infiltrating capabilities of T cells into 3D physiologic and tumorous scaffolds were assessed by flow cytometry. Lastly, hypoxic inhibition was validated as a target to sensitize BCa cells in order to overcome immune surveillance. Results: BCa cells grown in oxygen-deprived 3D tumorous environments showed a significant increase in the expression of HIF-1 alpha and a reduced cell proliferation compared to the BCa cells in 3D physiologic scaffolds. Increased secretion of collagen I, collagen III, laminin, and fibronectin was demonstrated by BCa cells in 3D tumorous compared to 3D physiologic scaffolds. T-cell infiltration (especially CD8 T cells) was significantly impaired within the oxygen-deprived breast cancer tumor microenvironment (TME), and hypoxia inhibition was further confirmed to resensitize BCa cells to cytotoxic CD8 T cells. Conclusions: Modeling of the oxygen-deprived breast cancer TME in our engineered 3D physiologic and tumorous scaffolds supported known intratumoral hypoxia characteristics such as reduced BCa cell proliferation, increased ECM expression, and hindered immune infiltration. Furthermore, hypoxic inhibition was validated as a target to sensitize BCa cells to immune surveillance. These models could serve as a promising platform for the evaluation of immunologic events as well as a drug-screening platform tool to overcome hypoxia-driven immune evasion. Citation Format: Somshuvra Bhattacharya, Kristin Calar, Claire Evans, Pilar de la Puente. Modeling the oxygen-deprived breast cancer tumor microenvironment within a three-dimensional bioengineered platform that exhibits hypoxia-driven immune evasion [abstract]. In: Proceedings of the AACR Special Conference on the Evolving Landscape of Cancer Modeling; 2020 Mar 2-5; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2020;80(11 Suppl):Abstract nr B29.

Introduction: Endothelial progenitor cells (EPCs) are a subtype of stem cells capable of differentiating into mature endothelial cells. Tumor-derived paracrine signals activate the bone marrow-residing EPCs to home to the tumor to promote angiogenesis. The aim of this study was to utilize the EPCs and their specific pathophysiologic homing to tumors as a biologically targeted drug-delivery system, as a novel “Trojan horse” cellular immunotherapy in cancer. Methods: To test the specificity of EPCs’ homing to cancer, chemotaxis of EPCs towards conditioned media derived from a series of cancer cell lines or towards nonconditioned media was performed in vitro using Boyden Chamber. In vivo biodistribution of EPCs was studied in diverse tumor models (localized and disseminated) of different cancers (myeloma, lymphoma, leukemia, breast, lung, pancreatic and glioma) after injecting EPCs intravenously, by analysis of the accumulation of EPCs in the tumors and other organs. To enhance the ability of EPCs to home to tumors, EPCs were “primed” in vitro by exposing them to conditioned media from hypoxic (1% O2) tumor cells, followed by testing the homing of “primed” EPCs to tumors, both in vitro and in vivo. Next, EPCs were loaded with LS-542 (NIR imaging dye), and with Titanocene (Tc) (a nontoxic compound used in phototherapy that can be activated by positrons to become toxic) and tested for the effect of the loading on viability and functionality of EPCs, using MTT and migration assays, respectively. Also, we tested the effect of Tc-loaded EPCs on killing of cancer cells when activated by 18FDG/PET. Results: We found that EPCs specifically homed to tumors in vitro and in vivo, in tumor size-dependent and time-dependent manner, and that EPCs selectively accumulated in tumor tissues, with significantly negligible amounts in other organs. Moreover, EPCs homed to primary tumors and followed the metastatic pattern of the tumor. Hypoxia “priming” of EPCs significantly improved their homing to cancer in vitro and in vivo. Loading EPCs with LS-542 or with Tc did not affect their viability or functionality. Additionally, Tc-loaded EPCs, when activated by 18FDG, induced a dose-dependent killing of cancer cells. Conclusions: EPCs have a highly specific and efficient biologic machinery to target tumors in as a pan-cancer phenomenon, especially when “primed” with hypoxic tumor media. Loading EPCs with LS-542 or Tc did not change their viability and functionality; thus, both are promising molecules for imaging and therapy of cancer. These results provide a proof of concept that EPCs can be used as a novel cellular immunotherapy for specific and efficacious delivery of theranostic agents in cancer. Also, unlike engineered/targeted immunotherapies such as cellular (CAR-T cells), bispecific T cell engagers, or monoclonal antibodies that target specific molecules on a specific tumor type, EPCs can be used as a pan-cancer “Trojan horse” drug-delivery platform due to the universality of (angiogenesis) in all cancer types. Citation Format: Barbara Muz, Pilar de la Puente, Shruti Shah, Cinzia Federico, Feda Azab, Justin King, Mark Fiala, Rui Tang, Partha Karmakar, Ravi Vij, Samuel Achilefu, Abdel Kareem Azab. Endothelial progenitor cells as drug-delivery Trojan horses for treatment and imaging of cancer [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr A27.

Introduction: Multiple myeloma (MM) is the second most prevalent hematologic malignancy. Chimeric antigen receptor (CAR)-T cells and bispecific T-cell engagers targeting BCMA, CS1, and CD38 are promising approaches for MM. However, using these targets individually limits the efficacy of these immunotherapy options due to the variable expression levels of these markers, leading to inefficient eradication of MM. Studies have attempted to develop CAR-T cells and T-cell engagers with multispecific targeting; however, these are still technically very challenging and are highly expensive. In this study, we developed nanoparticles with monovalent or multivalent specificity against MM targets and engage T cells, by chemical conjugation of monoclonal antibodies against each molecule to the surface of the liposome. Bi-specific nanoparticles with anti CD38/CD3, BCMA/CD3 or CS1/CD3 were termed nanoBiTEs, while the multispecific particles with anti BCMA/CS1/CD38/CD3 were termed nanoMuTEs. Methods: Liposomes were prepared using the thin-film hydration method followed by extrusion. nanoBiTEs and nanoMuTEs were developed by chemical conjugation of monoclonal antibodies against BCMA, CS1, and/or CD38; together with anti CD3 onto the liposomes. We have tested the expression of BCMA, CS1, and CD38 antigens in MM cell lines and primary MM patient samples, and we analyzed the binding of the CD38/CD3, BCMA/CD3, and CS1/CD3 nanoBiTEs, as well as the BCMA/CS1/CD38/CD3 nanoMuTEs to these cells by flow cytometry and confocal microscopy. Binding specificity was assessed by blocking the target with corresponding free antibodies. CD25 expression, a T-cell activation marker, was assessed for CD8 and CD4 T cells when incubated with or without nanoBiTEs and nanoMuTEs. Moreover, we tested the efficacy of the nanoBiTEs and nanoMuTEs against MM cells in vitro using the 3D tissue engineered bone marrow (3DTEBM) myeloma model. Finally, we tested the efficacy of the nanoBiTEs and nanoMuTE against MM tumors in vivo in xenograft MM models. Results: The expression of BCMA, CS1 and CD38 was variable in MM cell lines and patient samples, and so was the binding of each nanoBiTEs, while the binding of the nanoMuTE was higher and more universal than each nanoBiTE. Similar patterns were observed in activation of CD8 T cells (no significant activation was observed in CD4 T cells) and in eradication of MM cell lines and primary patient samples in vitro. In vivo, the nanoBiTEs extended the survival and reduced the tumor burden in the MM bearing mice compared to untreated and T cell alone groups, and nanoMuTE experiments are still ongoing. Conclusions: The nanoBiTEs and nanoMuTEs were bound specifically to MM cells and initiated CD8 T-cell activation that resulted in MM eradication in vitro and in vivo, while the effect of the nanoMuTEs was more universal and efficacious than each nanoBiTE. These nanoparticles are an inexpensive method of engaging T cells for the treatment of MM and represent a new class of immunotherapy that can be expanded to other tumors. Citation Format: Kinan Alhallak, Jennifer Sun, Barbara Muz, Christopher Egbulefu, Pilar de la Puente, Cinzia Federico, Justin King, Danny Kohnen, Ravi Vij, Samuel Achilefu, Abdel Kareem Azab. Nanoparticle multispecific T-cell engagers for the treatment of multiple myeloma [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr B01.

CD138 (also termed SDC1) has been the gold-standard surface marker to detect multiple myeloma (MM) cells for decades; however, drug-resistant residual and circulating MM cells were shown to have lower expression of this marker. In this study, we have shown that residual MM cells following bortezomib treatment are hypoxic. This combination of drug exposure and hypoxia down-regulates their CD138 expression, thereby making this marker unsuitable for detecting residual or other hypoxic MM cells, such as circulating tumour cells, in MM. Hence, we developed an alternative biomarker set which detects myeloma cells independent of their hypoxic and CD138 expression status in vitro, in vivo and in primary MM patients. The new markers were able to identify a clonal CD138-negative population as minimal residual disease in the bone marrow and peripheral blood of MM patients. Further investigation to characterize the role of this population as a prognostic marker in MM is warranted.

Despite recent progress in novel and targeted therapies, multiple myeloma (MM) remains a therapeutically challenging incurable disease. The regulation of important cellular processes and its link to cancer presented Src as an attractive target for MM. We suggest a novel strategy to improve the treatment of MM and overcome the drug resistance for the current therapeutic agents by specific inhibition of Src in MM cells by Tris (Dibenzylideneacetone) dipalladium (Tris DBA). Tris DBA reduces proliferation, induces G1 arrest and apoptosis in MM cells. Tris DBA showed additive effect with proteasome inhibitors reducing proliferation, cell cycle signaling, and increasing apoptosis more than each drug alone. Tris DBA overcame hypoxia-induced effects such as enhanced chemotaxis or drug resistance to proteasome inhibitors by inhibition of HIF1α expression. Moreover, we found that Tris DBA is an effective anti-myeloma agent alone or in combination with other targeted drugs and that it reverses hypoxia-induced drug resistance in myeloma.

Radiation-induced lymphopenia (RIL) is associated with treatment of different tumors (lung, colon, pancreas, breast, sarcomas, and glioblastoma). It is a significant clinical problem affecting the survival of cancer patients. The biologic mechanisms leading to RIL are not clearly understood. In this study, we established a mouse model of RIL representing therapeutic clinical regimen for lung cancer. Flow cytometry was used to analyze circulating levels of T and B cells and bone marrow (BM) stem cells. We found that fractionated radiation to the thorax significantly reduced circulating T and B cells as well as BM stem cells. Ex-vivo irradiation of blood and autologous reinjection to mice also significantly induced lymphopenia. Furthermore, we found that mobilization of stem cells from the BM and autologous stem cell transplant rescued RIL in mice. Overall, our results suggest that RIL has not only direct effect on circulating lymphocytes, but also has indirect effect on circulating lymphocytes as well as stem cells in the nonirradiated BM. These results open a new window for investigating the direct and indirect biologic mechanisms leading to RIL, and provide a preclinical basis to test the effect of stem cell transplantation for treatment of RIL in cancer patients. Cancer Res; 75(17); 3442–5. ©2015 AACR.

Multiple myeloma (MM) is a plasma cell malignancy localized in the bone marrow. Despite the introduction of novel therapies majority of MM patients relapse. We have previously shown that inhibition of P-selectin and P-selectin glycoprotein ligand-1 (PSGL-1) play a key role in proliferation of MM and using small-molecule inhibitors of P-selectin/PSGL-1 sensitized MM cells to therapy. However, these small-molecule inhibitors had low specificity to P-selectin and showed poor pharmacokinetics. Therefore, we tested blocking of P-selectin and PSGL-1 using functional monoclonal antibodies in order to sensitize MM cells to therapy. We have demonstrated that inhibiting the interaction between MM cells and endothelial and stromal cells decreased proliferation in MM cells and in parallel induced loose-adhesion to the primary tumor site to facilitate egress. At the same time, blocking this interactionin vivoled to MM cells retention in the circulation and delayed homing to the bone marrow, thus exposing MM cells to bortezomib which contributed to reduced tumor growth and better mice survival. This study provides a better understanding of the biology of P-selectin and PSGL-1 and their roles in dissemination and resensitization of MM to treatment.

The establishment of more effective treatments that can circumvent chemoresistance in Multiple Myeloma (MM) is a priority. Although bortezomib (BTZ) is one of the most potent proteasome inhibitors available, still possesses limitations related to dose limiting side effects. Several strategies have been developed to improve the delivery of chemotherapies to MM by targeting different moieties expressed on MM cells to nanoparticle delivery systems (NPs), which have failed mainly due to their heterogeneous expression on these cells. Our goal was to test CD38 targeted chitosan NPs as novel targeting moiety for MM to improve the potency and efficacy of BTZ in MM cells and reduce the side effects in healthy tissue. We have showed preferential BTZ release in tumor-microenvironment, specific binding to MM cells, and an improved drug cellular uptake through BTZ diffusion from the surface and endocytosed NPs, which translated in enhanced proteasome inhibition and robust cytotoxic effect on MM cells when BTZ was administered through anti-CD38 chitosan NPs. Furthermore, the anti-CD38 chitosan NPs specifically delivered therapeutic agents to MM cells improving therapeutic efficacy and reducing side effects in vivo. The anti-CD38 chitosan NPs showed low toxicity profile allowing enhancement of proteasome-inhibitory activity and specificity of BTZ by endocytosis-mediated uptake of CD38 representing a promising therapy in MM.

Overall survival of patients with newly diagnosed glioblastoma (GBM) remains dismal at 16 months with state-of-the-art treatment that includes surgical resection, radiation, and chemotherapy. GBM tumors are highly heterogeneous, and mechanisms for overcoming tumor resistance have not yet fully been elucidated. An injectable chitosan hydrogel capable of releasing chemotherapy (temozolomide [TMZ]) while retaining radioactive isotopes agents (iodine, [ 131 I]) was used as a vehicle for localized radiation and chemotherapy, within the surgical cavity. Release from hydrogels loaded with TMZ or 131 I was characterized in vitro and in vivo and their efficacy on tumor progression and survival on GBM tumors was also measured. The in vitro release of 131 I was negligible over 42 days, whereas the TMZ was completely released over the first 48 h. 131 I was completely retained in the tumor bed with negligible distribution in other tissues and that when delivered locally, the chemotherapy accumulated in the tumor at 10-fold higher concentrations than when delivered systemically. We found that the tumors were significantly decreased, and survival was improved in both treatment groups compared to the control group. Novel injectable chemo-radio-hydrogel implants may potentially improve the local control and overall outcome of aggressive, poor prognosis brain tumors.

Increased levels of the nuclear export protein, exportin 1 (XPO1), were demonstrated in multiple myeloma (MM) patients. Targeting XPO1 with selinexor (the selective inhibitor of nuclear export; SINE compound KPT-330) demonstrates broad antitumor activity also in patient cells resistant to bortezomib; hence, it is a promising target in MM patients. Hypoxia is known to mediate tumor progression and drug resistance (including bortezomib resistance) in MM cells. In this study, we tested the effects of selinexor alone or in combination with bortezomib in normoxia and hypoxia on MM cell survival and apoptosis in vitro and in vivo. In vitro, selinexor alone decreased survival and increased apoptosis, resensitizing MM cells to bortezomib. In vivo, we examined the effects of selinexor alone on tumor initiation and tumor progression, as well as selinexor in combination with bortezomib, on tumor growth in a bortezomib-resistant MM xenograft mouse model. Selinexor, used as a single agent, delayed tumor initiation and tumor progression, prolonging mice survival. In bortezomib-resistant xenografts, selinexor overcame drug resistance, significantly decreasing tumor burden and extending mice survival when combined with bortezomib.

Brachytherapy is described as the short distance treatment of cancer with a radioactive isotope placed on, in, or near the lesions or tumor to be treated. The main advantage of brachytherapy compared with external beam radiation (EBR) is the improved localized delivery of dose to the target volume of interest, thus normal tissue irradiation is reduced. The precise and targeted nature of brachytherapy provides a number of key benefits for the effective treatment of cancer such as efficacy, minimized risk of side effects, short treatment times, and cost-effectiveness. Brachytherapy devices have yielded promising results in preclinical and clinical studies. However, brachytherapy can only be used in localized and relatively small tumors. Although the introduction of new delivery devices allows the treatment of more complex tumor sites, with wider range of dose rate for improving treatment efficacy and reduction of side effects, a better understanding about the safety, efficacy, and accuracy of these systems is required, and further development of new techniques is warranted. Therefore, this review focuses on the delivery devices for brachytherapy and their application in prostate, breast, brain, and other tumor sites.

Tumor hypoxia is a well-described phenomenon during the progression of solid tumors affecting cell signaling pathways and cell metabolism; however, its role in hematologic malignancies has not been given the same attention in the literature. Therefore, this review focuses on the comparative differences between solid and hematologic malignancies with emphasis on the role of hypoxia during tumorigenesis and progression. In addition, contribution of the bone marrow and angiogenic environment are also discussed. Insight is provided into the role of hypoxia in metastatic spread, stemness, and drug resistance in hematologic conditions. Finally, emerging therapeutic strategies such as small-molecule prodrugs and hypoxia-inducible factor (HIF) targeting approaches are outlined to combat hypoxic cells and/or adaptive mechanisms in the treatment of hematologic malignancies. Mol Cancer Res; 12(10); 1347–54. ©2014 AACR.

In tissue engineering techniques, three-dimensional scaffolds are needed to adjust and guide cell growth and to allow tissue regeneration. The scaffold must be biocompatible, biodegradable and must benefit the interactions between cells and biomaterial. Some natural biomaterials such as fibrin provide a structure similar to the native extracellular matrix containing the cells. Fibrin was first used as a sealant based on pools of commercial fibrinogen. However, the high risk of viral transmission of these pools led to the development of techniques of viral inactivation and elimination and the use of autologous fibrins. In recent decades, fibrin has been used as a release system and three-dimensional scaffold for cell culture. Fibrin scaffolds have been widely used for the culture of different types of cells, and have found several applications in tissue engineering. The structure and development of scaffolds is a key point for cell culture because scaffolds of autologous fibrin offer an important alternative due to their low fibrinogen concentrations, which are more suitable for cell growth. With this review our aim is to follow methods of development, analyze the commercial and autologous fibrins available and assess the possible applications of cell culture in tissue engineering in these three-dimensional structures.

The phosphatidylinositide 3-kinase (PI3K) pathway is activated and correlated with drug resistance in multiple myeloma (MM). In the present study we investigated the role of PI3KCA (PI3K-α) in the progression and drug resistance in MM. We showed that the gene expression of PI3KCA isoform was higher in MM compared to normal subjects. BYL719, a novel and specific PI3KCA inhibitor inhibited the survival of primary MM cells and cell lines but not normal peripheral blood mononuclear cells. BYL719 induced the apoptosis of MM cells and inhibited their cell cycle by causing G1 arrest. BYL719 inhibited PI3K signalling, decreased proliferation and cells cycle signalling, and induced apoptosis signalling in MM cells. Finally, BYL719 synergized with bortezomib and carfilzomib, and overcame drug resistance induced by bone marrow stroma. These results were confirmed using in silico simulation of MM cell lines, BYL719 and bortezomib, and showed similar trends in survival, proliferation, apoptosis, cell signalling and synergy with drugs. In conclusion, PI3KCA plays a major role in proliferation and drug resistance of MM cells, the effects of which were inhibited with BYL719. These results provide a preclinical basis for a future clinical trial of BYL719 in MM as a single agent or in combination with other drugs.

Blood vessel formation plays an essential role in many physiologic and pathologic processes, including normal tissue growth and healing, as well as tumor progression. Endothelial progenitor cells (EPC) are a subtype of stem cells with high proliferative potential that are capable of differentiating into mature endothelial cells, thus contributing to neovascularization in tumors. In response to tumor-secreted cytokines, EPCs mobilize from the bone marrow to the peripheral blood, home to the tumor site, and differentiate to mature endothelial cells and secrete proangiogenic factors to facilitate vascularization of tumors. In this review, we summarize the expression of surface markers, cytokines, receptors, adhesion molecules, proteases, and cell signaling mechanisms involved in the different steps (mobilization, homing, and differentiation) of EPC trafficking from the bone marrow to the tumor site. Understanding the biologic mechanisms of EPC cell trafficking opens a window for new therapeutic targets in cancer. Clin Cancer Res; 19(13); 3360–8. ©2013 AACR.

Boron neutron capture therapy (BNCT) has the potential to become a viable cancer treatment modality, but its clinical translation has been limited by the poor tumor selectivity of agents. To address this unmet need, a boronated 2-nitroimidazole derivative (B-381) was synthesized and evaluated for its capability of targeting hypoxic glioma cells.B-381 has been synthesized from a 1-step reaction. Using D54 and U87 glioma cell lines, the in vitro cytotoxicity and cellular accumulation of B-381 has been evaluated under normoxic and hypoxic conditions compared to L-boronophenylalanine (BPA). Furthermore, tumor retention of B-381 was evaluated in vivo.B-381 had low cytotoxicity in normal and cancer cells. Unlike BPA, B-381 illustrated preferential retention in hypoxic glioma cells compared to normoxic glioma cells and normal tissues in vitro. In vivo, B-381 illustrated significantly higher long-term tumor retention compared to BPA, with 9.5-fold and 6.5-fold higher boron levels at 24 and 48 h, respectively.B-381 represents a new class of BNCT agents in which their selectivity to tumors is based on hypoxic tumor metabolism. Further studies are warranted to evaluate B-381 and similar compounds as preclinical candidates for future BNCT clinical trials for the treatment of glioma.

Background: Multiple Myeloma (MM) is the second most common hematological malignancy, and continues to be a fatal disease even with the development of novel therapies. Despite promising preclinical data in standard tissue culture models, most drugs fail in clinical trials and show lower efficacy in patients. This highlights the discrepancy between the current in vitro models, the pathophysiology of the disease in the patients, and the urgent need for better in vitro models for drug development and improved prediction of efficacy in patients. We have previously developed a patient-derived 3D-Tissue Engineered Bone Marrow (3DTEBM) culture model, which showed superior properties for proliferation of primary MM cells ex vivo, and better recapitulated drug resistance. The long-term goal of this study is to use the 3DTEBM model as a tool to perform drug screens on BM aspirates of MM patients and prospectively predict the efficacy of different therapies in individual patients, and help treatment providers develop personalized treatment plans for each individual patient. In the current study, we used the 3DTEBM model to, retrospectively, predict clinical responses of MM patients to therapy, as a proof of concept. Methods: We used whole-BM, viably frozen tissue banked samples from 20 MM patients with clear clinical response patterns of complete remission, and either very good partial response (sensitive) or progressive disease (non-sensitive). The BM aspirates were used to develop a 3DTEBM that represents each individual patient. The patient-derived 3DTEBM cultures were treated ex vivo with the same therapeutic regimen that the patient received in the clinic for 3 days. The treatment ex vivo was based on combinations at different concentrations which mimic the steady state concentrations (Css) of each drug. The efficacy of the treatment ex vivo was evaluated by digestion of the 3DTEBM matrix, extraction of the cells, and analysis for prevalence of MM cells in the treatment groups compared to the non-treated controls. Patients were defined "sensitive" if the effect reached 50% killing in the range of 10xCss. The ex vivo sensitivity data was then correlated with the clinical response outcomes. Results: We found that the 3DTEBM was predictive in approximately 80% of the cases (in about 85% of the combination therapy cases, and in about 70% of the single therapy cases). Broken down by individual drug, it was predictive in 80% of the cases treated with Bortezomib, 78% Lenalidomide, 84% Dexamethasone, 100% Daratumumab, 50% Carfilzomib, 50% Pomalidomide, and 100% Doxorubicin. Conclusions: The 3DTEBM is a more pathophysiologically relevant model which predicts clinical efficacy of drugs in multiple myeloma patients, retrospectively. This data provides the bases for future studies which will examine the ability of the 3DTEBM model to predict treatment efficacy, prospectively, for development of personalized treatment plans in individual multiple myeloma patients. Disclosures Jeske: Cellatrix LLC: Employment. Azab:Cellatrix LLC: Employment. De La Puente:Cellatrix LLC: Other: Co-founder. Vij:Jazz Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Karyopharma: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Jansson: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Azab:Ach Oncology: Research Funding; Cellatrix LLC: Equity Ownership, Other: Founder and owner; Glycomimetics: Research Funding; Targeted Therapeutics LLC: Equity Ownership, Other: Founder and owner.

Purpose Multiple myeloma (MM) is the second most prevalent hematological malignancy and it remains incurable despite the introduction of several novel drugs. The discrepancy between preclinical and clinical outcomes can be attributed to the failure of classic two-dimensional (2D) culture models to accurately recapitulate the complex biology of MM and drug responses observed in patients. Experimental design: We developed 3D tissue engineered bone marrow (3DTEBM) cultures derived from the BM supernatant of MM patients to incorporate different BM components including MM cells, stromal cells, and endothelial cells. Distribution and growth were analyzed by confocal imaging, and cell proliferation of cell lines and primary MM cells was tested by flow cytometry. Oxygen and drug gradients were evaluated by immunohistochemistry and flow cytometry, and drug resistance was studied by flow cytometry. Results 3DTEBM cultures allowed proliferation of MM cells, recapitulated their interaction with the microenvironment, recreated 3D aspects observed in the bone marrow niche (such as oxygen and drug gradients), and induced drug resistance in MM cells more than 2D or commercial 3D tissue culture systems. Conclusions 3DTEBM cultures not only provide a better model for investigating the pathophysiology of MM, but also serve as a tool for drug development and screening in MM. In the future, we will use the 3DTEBM cultures for developing personalized therapeutic strategies for individual MM patients.

Current treatment options as well as clinical efficacy are limited for chronic myelogenous leukemia (CML), Ph+ acute lymphoblastic leukemia (ALL), and acute myeloid leukemia (AML). In response to the pressing need for more efficacious treatment approaches and strategies to override drug resistance in advanced stage CML, Ph+ ALL, and AML, we investigated the effects of inhibition of ILK as a potentially novel and effective approach to treatment of these challenging malignancies. Using the small molecule ILK inhibitor, Cpd22, and ILK knockdown, we investigated the importance of ILK in the growth and viability of leukemia. Our results suggest that the ILK inhibition may be an effective treatment for CML, Ph+ ALL, and AML as a single therapy, with ILK expression levels positively correlating with the efficacy of ILK inhibition. The identification of ILK as a novel target for leukemia therapy warrants further investigation as a therapeutic approach that could be of potential clinical benefit in both acute and chronic myeloid leukemias.

Boron neutron capture therapy (BNCT) is a promising cancer therapy modality that utilizes the nuclear capture reaction of epithermal neutrons by boron-10 resulting in a localized nuclear fission reaction and subsequent cell death. Since cellular destruction is limited to approximately the diameter of a single cell, primarily only cells in the neutron field with significant boron accumulation will be damaged. However, the emergence of BNCT as a prominent therapy has in large part been hindered by a paucity of tumor selective boron containing agents. While L-boronophenylalanine and sodium borocaptate are the most commonly investigated clinical agents, new agents are desperately needed due to their suboptimal tumor selectivity. This review will highlight the various strategies to improve tumor boron delivery including: nucleoside and carbohydrate analogs, unnatural amino acids, porphyrins, antibody-dendrimer conjugates, cationic polymers, cell-membrane penetrating peptides, liposomes and nanoparticles.

Waldenström macroglobulinemia, a rare and indolent type of non–Hodgkin lymphoma, is characterized by widespread lymphoplasmacytic B cells in the bone marrow. Previous studies have shown that hypoxic conditions play a key role in the dissemination of other hematologic malignancies. In this study, the effect of hypoxia was tested on the progression and spread of Waldenström macroglobulinemia. Interestingly, tumor progression correlated with hypoxia levels in Waldenström macroglobulinemia cells and other cells in the bone marrow and correlated with the number of circulating tumor cells in vivo. Mechanistic studies demonstrated that hypoxia decreased cell progression and cell cycle, did not induce apoptosis, and reduced the adhesion between Waldenström macroglobulinemia cells and bone marrow stroma, through downregulation of E-cadherin expression, thus explaining increased egress of Waldenström macroglobulinemia cells to the circulation. Moreover, hypoxia increased the extravasation and homing of Waldenström macroglobulinemia cells to new bone marrow niches in vivo, by increased CXCR4/SDF-1–mediated chemotaxis and maintaining the VLA4-mediated adhesion. Re-oxygenation of hypoxic Waldenström macroglobulinemia cells enhanced the rate of proliferation and cell cycle progression and restored intercellular adhesion between Waldenström macroglobulinemia cells and bone marrow stroma. This study suggests that targeting hypoxic response is a novel strategy to prevent dissemination of Waldenström macroglobulinemia. Implications: This study provides a better understanding of the biology of dissemination of Waldenström macroglobulinemia and opens new windows for investigation of new therapeutic targets in Waldenström macroglobulinemia based on tumor hypoxia mechanisms. Mol Cancer Res; 13(2); 263–72. ©2014 AACR.