Resistance to the cytotoxic effects of many natural product drugs after exposure to a single agent is a common observation. The classes of drugs included in the "classic" multiple drug resistance phenotype are Vinca alkaloids, anthracyclines, epipodophyllotoxins, and antibiotics. We re port here the characterization of a human leukemic cell line (CEM/VM1) with "atypical" multiple drug resistanc...

The 6-epimer of the plakortide H acid (1), along with the endoperoxides plakortide E (2), plakortin (3), and dihydroplakortin (4) have been isolated from a sample of the Caribbean sponge Plakortis halichondrioides. To perform a comparative study on the cytotoxicity towards the drug-sensitive leukemia CCRF-CEM cell line and its multi-drug resistant subline CEM/ADR5000, the acid of plakortin, nam...

Derivatives of the CEM T and WIL-2 B cell lines showed striking diversity in their responses to the HTLV-IIIB strain of the human immunodeficiency virus (HIV). Several stable phenotypic patterns could be defined, based on whether cells were permissive (P+, P-) for virus production, were sensitive or insensitive to cytopathic effects after infection by free virus (C+, C-), and whether they under...

We analyzed the patterns of glycosphingolipids (GSLs) from a line of cells derived from a clone of the human T-cell leukemia cells (CEM) that had been induced to differentiate by phorbol-12-myristate-13-acetate (PMA) into cells with a suppressor-like phenotype. We characterized the differentiation state of the cells by immunofluorescence by using anti-cell surface differentiation-specific monoc...

Natural retinoids and curcuminoids are known for their broad spectrum of biological properties, such as antioxidant, anti-inflammatory, antitumor, and so forth. In this work, a convenient synthesis of aromatic retinoids and curcuminoids from vinyl or allyl ketones, and the corresponding alcohols, using olefin metathesis as a key reaction, was elaborated. The best yields and diastereoselectiviti...

We examined the effect of tamoxifen (Tmx), verapamil, and daunorubicin (DNR) in two cell lines that displayed the multidrug-resistant (MDR) phenotype and used laser flow cytometry to quantitate intracellular DNR content. In the vinblastine-resistant human lymphoblastic lymphoma cell line CEM-VBL, simultaneous incubation of DNR with Tmx 10 mumol/L or Tmx 50 mumol/L increased intracellular DNR fl...

Glucocorticoid (GC) hormones induce apoptosis in T-cell and pre-B-cell acute lymphoblastic leukemia (ALL) cells. Steroid-mediated apoptosis requires a threshold level of the glucocorticoid receptor (GR) protein, and increasing the intracellular GR levels in ALL cells would augment their hormone sensitivity. A protein transduction domain (PTD) approach was used to accomplish this. We produced an...

The dichloromethane extract of the flowers of Helianthus angustifolius L. (Asteraceae, Heliantheae) was investigated in vitro for its cytotoxic activity using human cancer cell lines: CCRF-CEM leukemia, MDA-MB-231 breast cancer, U251 glioblastoma, HCT 116 colon cancer cells, and the human lung fibroblast cell line MRC-5. Cytotoxicity-guided fractionation led to the isolation of four related hel...

The Tibetan herbal remedy PADMA 28 revealed promising results to support treatment of atherosclerosis, Charot syndrome (intermittent claudication), chronic active hepatitis and infection of the respiratory tract. The remedy was confirmed to be closely linked with anti- and pro-oxidative properties in vitro. In this study, apoptogenic and survival effects of PADMA 28 were investigated in the T c...

Iron-transferrin (FeTF) is an essential growth factor required for proliferation of lymphoid cells. FeTF activates protein kinase C (PKC) in the lymphoblastoid T-cell line, CCRF-CEM. We have treated CEM cells with human FeTF, then examined levels of PKC mRNA by hybridization analysis using cDNA probes specific for a-, p-, and yPKC subspecies. CEM cell mRNA hybridized with the p-subspecies probe...