15-Methylene-Eburnamonine Kills Leukemic Stem Cells and Reduces Engraftment in a Humanized Bone Marrow Xenograft Mouse Model of Leukemia.

Recent studies suggest that leukemia stem cells (LSCs) play a critical role in the initiation, propagation, and relapse of leukemia. Herein we show that (-)-15-methylene-eburnamonine, a derivative of the alkaloid (-)-eburnamonine, is cytotoxic against acute and chronic lymphocytic leukemias (ALL and CLL) and acute myelogenous leukemia (AML). The agent also decreases primary LSC frequency in vitro.

1α,25-Dihydroxyvitamin D Inhibits the Metastatic Capability of MCF10CA1a and MDA-MB-231 Cells in an In Vitro Model of Breast to Bone Metastasis.

Breast cancer metastasis to the bone continues to be a major health problem, with approximately 80% of advanced breast cancer patients expected to develop bone metastasis. Although the problem of bone metastasis persists, current treatment options for metastatic cancer patients are limited. In this study, we investigated the preventive role of the active vitamin D metabolite, 1α,25-dihydroxyvitamin D (1,25(OH)2D), against the metastatic potential of breast cancer cells using a novel three-dimensional model (rMET) recapitulating multiple steps of the bone metastatic process.

Maytansinoid immunoconjugate IMGN901 is cytotoxic in a three-dimensional culture model of multiple myeloma.

Environmental-mediated drug-resistance (EM-DR) presents a major challenge for therapeutic development. Tissue microenvironment in the form of extracellular matrix, soluble factors, and stroma contribute to EM-DR. In multiple myeloma (MM), drug-resistance has hindered treatment success with 5-year survival rates remaining <50%.

A reconstructed metastasis model to recapitulate the metastatic spread in vitro.

Metastasis remains a leading cause of morbidity and mortality from solid tumors. Lack of comprehensive systems to study the progression of metastasis contributes to the low success of treatment. We developed a novel three-dimensional in vitro reconstructed metastasis (rMet) model that incorporates extracellular matrix (ECM) elements characteristic of the primary (breast, prostate, or lung) and metastatic (bone marrow, BM) sites.

N-cadherin impedes proliferation of the multiple myeloma cancer stem cells.

Multiple myeloma (MM) is an incurable malignancy of the plasma cells localized to the bone marrow. A rare population of MM cancer stem cells (MM-CSCs) has been shown to be responsible for maintaining the pull of residual disease and to contribute to myeloma relapse. The stem cells are found in a bone marrow niche in contact with the stromal cells that are responsible for maintaining the proliferative quiescence of the MM-CSC and regulate its self-renewal and differentiation decisions.

Dkk-1 and IL-7 in plasma of patients with multiple myeloma prevent differentiation of mesenchymal stem cells into osteoblasts.

Bone disease is the leading cause of morbidity associated with multiple myeloma (MM). Lytic bone lesions have been detected in 90% of patients diagnosed with MM and present a great therapeutic challenge. After the removal of the tumor burden, the bone lesions persist and the bone remodeling homeostasis is not restored even in patients in clinical remission.

Differentiation of cancer cells in two-dimensional and three-dimensional breast cancer models by Raman spectroscopy.

We demonstrate the first application of Raman spectroscopy in diagnosing nonmalignant, premalignant, malignant, and metastatic stages of breast cancer in a three-dimensional (3-D) cell culture model that closely mimics an in vivo environment. Comprehensive study comparing classification in two-dimensional (2-D) and 3-D cell models was performed using statistical methods composed of principal component analysis for exploratory analysis and outlier removal, partial least squares discriminant analysis, and elastic net regularized regression for classification. Our results show that Raman spectroscopy with an appropriate classification tool has excellent resolution to discriminate the four stages of breast cancer progression, with a near 100% accuracy for both 2-D and 3-D cell models.

Synthesis of 15-methylene-eburnamonine from (+)-vincamine, evaluation of anticancer activity, and investigation of mechanism of action by quantitative NMR.

The biological role of installing a critical exocyclic enone into the structure of the alkaloid, (-)-eburnamonine, and characterization of the new chemical reactivity by quantitative NMR without using deuterated solvents are described. This selective modification to a natural product imparts potent anticancer activity as well as bestows chemical reactivity toward nucleophilic thiols, which was measured by quantitative NMR. The synthetic strategy provides an overall conversion of 40%.

The systemic cytokine environment is permanently altered in multiple myeloma.

Multiple myeloma (MM) is an incurable bone marrow malignancy of the B cell lineage. Utilizing multiplex Luminex technology we measured levels of 25 cytokines in the plasma of normal donors (n = 177), those with monoclonal gammopathy of undetermined significance (n = 8), and MM patients (n = 55) with either active disease, on treatment, or in remission. The cytokine levels were compared between normal donors and MM patients as well as between various phases of MM, and discriminant analysis was used to create a predictive classification model based on the differentially expressed cytokines.

Exploiting the facile release of trifluoroacetate for the α-methylenation of the sterically hindered carbonyl groups on (+)-sclareolide and (-)-eburnamonine.

An efficient method for the α-methylenation of carbonyl groups is reported, and this transformation is accomplished by a facile elimination of trifluoroacetate during the formation of the olefin. This method represents an improvement beyond existing protocol in cases of steric hindrance, and we have demonstrated the utility of the process across a series of ketones, lactams, and lactones. Additionally, we have applied this method to produce semisynthetic derivatives of the natural products (+)-sclareolide and (-)-eburnamonine, in which the carbonyl group is proximal to bulky functional groups.

The natural products parthenolide and andrographolide exhibit anti-cancer stem cell activity in multiple myeloma.

Multiple myeloma (MM) is an incurable plasma cell malignancy where nearly all patients succumb to a relapse. The current preclinical models of MM target the plasma cells, constituting the bulk of the tumor, leaving the cancer stem cells to trigger a relapse. Utilizing a three-dimensional tissue culture system where cells were grown in extracellular matrix designed to reconstruct human bone marrow, we tested the anti-multiple myeloma cancer stem cell (MM-CSC) potential of two natural product inhibitors of nuclear factor κB (NFκB).

In a patient with biclonal Waldenstrom macroglobulinemia only one clone expands in three-dimensional culture and includes putative cancer stem cells.

A small percentage of cases of Waldenstrom macroglobulinemia (WM) present with biclonality, defined here as the rearrangement of two distinct VDJ gene segments. Here we investigated the expansion of two clones from a patient with WM expressing molecularly detectable clonotypic gene rearrangements, one V(H)3 and one V(H)4. Biclonality was determined in blood and bone marrow mononuclear cells using real-time quantitative PCR (RQ-PCR).

Altered expression of fibronectin and collagens I and IV in multiple myeloma and monoclonal gammopathy of undetermined significance.

Multiple myeloma (MM) is an incurable B-cell malignancy that arises in the bone marrow (BM). The malignant cells within the BM have extensive interaction with the structural components of their microenvironment. It has been previously shown that the interactions between MM cells and the BM extracellular matrix (ECM) proteins contribute to drug resistance.

A unique three-dimensional model for evaluating the impact of therapy on multiple myeloma.

Although the in vitro expansion of the multiple myeloma (MM) clone has been unsuccessful, in a novel three-dimensional (3-D) culture model of reconstructed bone marrow (BM, n = 48) and mobilized blood autografts (n = 14) presented here, the entire MM clone proliferates and undergoes up to 17-fold expansion of malignant cells harboring the clonotypic IgH VDJ and characteristic chromosomal rearrangements. In this system, MM clone expands in a reconstructed microenvironment that is ideally suited for testing specificity of anti-MM therapeutics. In the 3-D model, melphalan and bortezomib had distinct targets, with melphalan targeting the hematopoietic, but not stromal com-partment.

Mutation analysis of the short cytoplasmic domain of the cell-cell adhesion molecule CEACAM1 identifies residues that orchestrate actin binding and lumen formation.

CEACAM1-4S (carcinoembryonic antigen cell adhesion molecule 1, with 4 ectodomains and a short, 12-14 amino acid cytoplasmic domain) mediates lumen formation via an apoptotic and cytoskeletal reorganization mechanism when mammary epithelial cells are grown in a three-dimensional model of mammary morphogenesis. We show by quantitative yeast two-hybrid, BIAcore, NMR HSQC and STD, and confocal analyses that amino acids phenylalanine (Phe(454)) and lysine (Lys(456)) are key residues that interact with actin orchestrating the cytoskeletal reorganization. A CEACAM1 membrane model based on vitamin D-binding protein that predicts an interaction of Phe(454) at subdomain 3 of actin was supported by inhibition of binding of actin to vitamin D-binding protein by the cytoplasmic domain peptide.

Inhibition of transforming growth factor-beta1 signaling attenuates ataxia telangiectasia mutated activity in response to genotoxic stress.

Ionizing radiation causes DNA damage that elicits a cellular program of damage control coordinated by the kinase activity of ataxia telangiectasia mutated protein (ATM). Transforming growth factor beta (TGFbeta)-1, which is activated by radiation, is a potent and pleiotropic mediator of physiologic and pathologic processes. Here we show that TGFbeta inhibition impedes the canonical cellular DNA damage stress response.

Cell-cell adhesion molecule CEACAM1 is expressed in normal breast and milk and associates with beta1 integrin in a 3D model of morphogenesis.

CEA cell adhesion molecule-1 (CEACAM1) is a cell-cell adhesion molecule that, paradoxically, is expressed in an apical location in normal breast epithelium. Strong lumenal membrane staining is observed in 100% of normal glands (11/11), low in atypical hyperplasia (2/6), high in cribiform ductal carcinoma in situ (DCIS) (8/8), but low in other types of DCIS (2/15). Although most invasive ductal carcinomas express CEACAM1 (21/26), the staining pattern tends to be weak and cytoplasmic in tumours with minimal lumena formation (grades 2-3), while there is membrane staining in well-differentiated tumours (grade 1).

Characterization of recombinant soluble carcinoembryonic antigen cell adhesion molecule 1.

Carcinoembryonic antigen cell adhesion molecule 1 (CEACAM1) is a type 1 transmembrane, homotypic cell adhesion protein expressed on epithelial and hematopoietic cells. CEACAM1 has four major isoforms with three or four immunoglobulin (Ig)-like ectodomains and either long or short cytoplasmic domains. In a 3D model of breast epithelial cell morphogenesis, CEACAM1 plays an essential role in lumen formation [J.

CEACAM1, a cell-cell adhesion molecule, directly associates with annexin II in a three-dimensional model of mammary morphogenesis.

The epithelial cell adhesion molecule CEACAM1 (carcinoembryonic antigen cell adhesion molecule-1) is down-regulated in colon, prostate, breast, and liver cancer. Here we show that CEACAM1-4S, a splice form with four Ig-like ectodomains and a short cytoplasmic domain (14 amino acids), directly associates with annexin II, a lipid raft-associated molecule, which is also down-regulated in many cancers. Annexin II was identified using a glutathione S-transferase pull-down assay in which the cytoplasmic domain of CEACAM-4S was fused to glutathione S-transferase, the fusion protein was incubated with cell lysates, and isolated proteins were sequenced by mass spectrometry.

CEACAM1-4S, a cell-cell adhesion molecule, mediates apoptosis and reverts mammary carcinoma cells to a normal morphogenic phenotype in a 3D culture.

In a 3D model of breast morphogenesis, CEACAM1 (carcinoembryonic antigen-related cell adhesion molecule 1) plays an essential role in lumen formation in a subline of the nonmalignant human breast cell line (MCF10A). We show that mammary carcinoma cells (MCF7), which do not express CEACAM1 or form lumena when grown in Matrigel, are restored to a normal morphogenic program when transfected with CEACAM1-4S, the short cytoplasmic isoform of CEACAM1 that predominates in breast epithelia. During the time course of lumen formation, CEACAM1-4S was found initially between the cells, and in mature acini, it was found exclusively in an apical location, identical to its expression pattern in normal breast.