Abstract: A hybridoma (termed "UIC2 hybridoma", ATCC Accession No. HB11027) producing monoclonal antibodies (termed "UIC2 mAb") directed against an extracellular domain of a cell surface P-glycoprotein antigen associated with multidrug resistance in primate cells was produced by fusing a human myeloma cell with a spleen cell derived from a BALB/c mouse immunized with syngeneic 3T3 fibroblasts previously transfected with the isolated human mdr1 cDNA. UIC2 mAb, thus produced, as well as fragments and recombinant derivatives thereof, may be used to detect and isolate multidrug resistant primate cells and human mdr1 gene products, and to reverse multidrug resistance in primate cells, including cells of multidrug resistant human tumors.

Abstract: This invention relates to immunological reagents and methods specific for a mammalian, transmembrane protein termed Pgp, having a non-specific efflux pump activity established in the art as being a component of clinically-important multidrug resistance in cancer patients undergoing chemotherapy. The invention provides methods for developing and using immunological reagents specific for certain mutant forms of Pgp and for wild-type Pgp in a conformation associated with substrate binding or in the presence of ATP depleting agents. The invention also provides improved methods for purifying hematopoietic stems cells expressing Pgp and diagnostic and therapeutic methods for cancer cells expressing Pgp.

Abstract: This invention is directed to methods for preventing the emergence of multidrug resistance in tumor cells during cancer chemotherapy. In particular, it relates to the use of protein kinase inhibitors to prevent the induction of expression of the multidrug resistance gene (MDR1) encoding P-glycoprotein by chemotherapeutic drugs. MDR1 expression, which results in tumor cell resistance to subsequent treatment with certain chemotherapeutic drugs, is shown herein to be induced in response to treatment with various cytotoxic agents, including such agents that are and are not substrates for P-glycoprotein-mediated efflux from cancer cells. Inhibitors of protein kinases, in particular, protein kinase C, are shown herein to suppress this cellular response. In addition, such protein kinase inhibitors are also shown herein to inhibit expression of a gene encoding a multidrug resistance-associated protein (the MRP gene).

Abstract: The invention provides genetic suppressor elements that confer upon a cell resistance to platinum-based drugs, including cisplatin, methods for identifying and obtaining such elements, and methods of using such elements. The invention also provides cloned genes associated with sensitivity to cisplatin.

Abstract: The invention provides methods for purifying or manipulating bone marrow and blood cells based upon P-glycoprotein expression. The methods rely upon immunopurification procedures or upon differential accumulation of materials subject to P-glycoprotein mediated efflux.

Abstract: The invention provides genetic suppressor elements that confer upon a cell resistance to one or more chemotherapeutic drug, methods for identifying and obtaining such elements, and methods of using such elements. The invention also provides cloned genes associated with sensitivity to chemotherapeutic drugs, particularly a cloned human kinesin heavy chain gene involved in resistance to DNA damaging agents.

Abstract: Methods for isolating and identifying genetic elements that are capable of inhibiting gene function are disclosed, as well as genetic elements isolated or identified according to the method of the invention and host cells modified by genetic modification using genetic suppressor elements according to the invention.

Abstract: The invention provides genetic suppressor elements that are derived from the apoptosis-related gene BCL2. The invention provides genetic suppressor elements that are capable of inhibiting BCL2 gene expression and BCL2-mediated suppression of apoptosis in mammalian cells. The GSEs provided by the invention are also useful for sensitizing cancer cells to the cytotoxic effects of chemotherapeutic drugs. The invention provides methods for identifying and obtaining such elements, and therapeutic methods of using such elements for treatment of cancer cells and animals bearing malignant tumors.

Abstract: Hybridomas (termed "UIC2 hybridoma", ATCC Accession No. HB11027 and "UIC2/A hybridoma", ATCC Accession No. HB11287) producing a monoclonal antibody (termed "UIC2 mAb") directed against an extracellular domain of a cell surface P-glycoprotein antigen associated with multidrug resistance in primate cells was produced by fusing a human myeloma cell with a spleen cell derived from a Balb/c mouse immunized with syngeneic 3T3 fibroblasts previously transfected with the isolated human mdr1 cDNA. UIC2 mAb, thus produced, as well as fragments and recombinant derivatives thereof, may be used to detect and isolate multidrug resistant primate cells and human mdr1 gene products, and to reverse multidrug resistance in primate cells, including cells of multidrug resistant human tumors.

Abstract: The invention provides genetic suppressor elements that confer the transformed phenotype of malignant mammalian cells upon untransformed cells, methods for identifying and obtaining such elements, methods for isolating and identifying genes corresponding to such elements, and methods of using such elements. The invention also provides genes corresponding to the GSEs of the invention.

Abstract: The invention provides genetic suppressor elements that confer upon a cell resistance to one or more chemotherapeutic drug, methods for identifying and obtaining such elements, and methods of using such elements. The invention also provides cloned genes associated with sensitivity to chemotherapeutic drugs.

Abstract: The invention provides methods for purifying or manipulating bone marrow and blood cells based upon P-glycoprotein expression. The methods rely upon immunopurification procedures or upon differential accumulation of materials subject to P-glycoprotein mediated efflux.

Abstract: A hybridoma (termed "UIC2 hybridoma", ATCC Accession No. HB11207) producing monoclonal antibodies (termed "UIC2 mAb") directed against an extracellular domain of a cell surface P-glycoprotein antigen associated with multidrug resistance in primate cells was produced by fusing a human myeloma cell with a spleen cell derived from a BALB/c mouse immunized with syngeneic 3T3 fibroblasts previously transfected with the isolated human mdr1 cDNA. UIC2 mAb, thus produced, as well as fragments and recombinant derivatives thereof, may be used to detect and isolate multidrug resistant primate cells and human mdr1 gene products, and to reverse multidrug resistance in primate cells, including cells of multidrug resistant human tumors.

Abstract: Methods for isolating and identifying genetic elements that are capable of inhibiting gene function are disclosed, as well as genetic elements isolated or identified according to the method of the invention and host cells modified by genetic modification using genetic suppressor elements according to the invention.

Abstract: Genomic and cDNA clones of human genes which are selectively amplified or overexpressed in multidrug-resistant human tumor cells were isolated. Such clones may be used as probes in diagnostic tests to detect chemotherapy-resistant tumor cells and to predict tumor response to chemotherapy. The complete nucleotide sequence of the coding region of the human mdr1 gene and the complete corresponding amino acid sequence are disclosed.