Skip to main content
eScholarship
Open Access Publications from the University of California

Scholarly Works (4 results)

  • Article
  • Peer Reviewed
UC Irvine Previously Published Works (2012)

The chemokine receptor CXCR4, which normally regulates stromal stem cell interactions in the bone marrow, is highly expressed on a variety of malignant hematologic cells, including lymphoma and lymphocytic leukemias. A new treatment concept has arisen wherein CXCR4 may be an effective therapeutic target as an adjunct to treatment of hematologic neoplasms with chemo- and immunotherapy. In the present study, we developed pepducins, cell-penetrating lipopeptide antagonists of CXCR4, to interdict CXCL12-CXCR4 transmembrane signaling to intracellular G-proteins. We demonstrate that pepducins targeting the first (i1) or third (i3) intracellular loops of CXCR4 completely abrogate CXCL12-mediated cell migration of lymphocytic leukemias and lymphomas. Stromal-cell coculture protects lymphoma cells from apoptosis in response to treatment with the CD20-targeted Ab rituximab. However, combination treatment with CXCR4 pepducins and rituximab significantly increases the apoptotic effect of rituximab. Furthermore, treatment of mice bearing disseminated lymphoma xenografts with pepducins alone or in combination with rituximab significantly increased their survival. These data demonstrate that CXCL12-CXCR4 signaling can be effectively inhibited by cell-penetrating pepducins, which represents a potential new treatment strategy for lymphoid malignancies.

    Cover page: Targeting CXCR4 with cell-penetrating pepducins in lymphoma and lymphocytic leukemia.
    • Article
    • Peer Reviewed
    UC Irvine Previously Published Works (2018)
    BACKGROUND: The monoclonal antibody daratumumab, approved for treating myeloma, targets CD38, a protein on myeloma and also on CD34+ hematopoietic progenitor cells. Because mobilized CD34+ cells are critical for stem cell transplant, we investigated the in vitro activity of daratumumab on mobilized CD34+ cells from myeloma patients with no prior exposure to daratumumab. METHODS: We determined the number of CD38 molecules per CD34+ cell, and whether daratumumab bound to CD34+ cells, whether C1q bound to daratumumab-coated CD34+ cells and whether daratumumab-related complement-dependent cytotoxicity (CDC) occurred. We also examined CD34+ cell progenitor cell colony capacity in assays with pre-plating incubation of CD34+ cells with daratumumab alone or with daratumumab and the CD59 inhibitory antibody BRIC229, and also assessed CD34+ cell responses to increasing doses of daratumumab in caspase 3/7 activity assays. RESULTS: Although 75% of mobilized CD34+ cells co-express CD38, CD38 was minimally present on CD34+ cells compared to Daudi and KG-1 controls, C1q did not bind to daratumumab-coated CD34+ cells, and CDC did not occur. CD34+ cells incubated in complement-rich human serum with daratumumab alone or with daratumumab and BRIC229, and then plated in progenitor cell assays, produced similar numbers of colonies as controls. In progenitor cell assays with cryopreserved or fresh unselected or CD34-selected cells, daratumumab did not affect progenitor cell capacity, and in caspase 3/7 activity assays CD34+ cells were not affected by increasing doses of daratumumab. CONCLUSION: In vitro, daratumumab is not toxic to mobilized CD34+ progenitor cells from myeloma patients.
      Cover page: Daratumumab binds to mobilized CD34+ cells of myeloma patients in vitro without cytotoxicity or impaired progenitor cell growth.
      • Article
      • Peer Reviewed
      UC Irvine Previously Published Works (2018)

      Background

      The monoclonal antibody daratumumab, approved for treating myeloma, targets CD38, a protein on myeloma and also on CD34+ hematopoietic progenitor cells. Because mobilized CD34+ cells are critical for stem cell transplant, we investigated the in vitro activity of daratumumab on mobilized CD34+ cells from myeloma patients with no prior exposure to daratumumab.

      Methods

      We determined the number of CD38 molecules per CD34+ cell, and whether daratumumab bound to CD34+ cells, whether C1q bound to daratumumab-coated CD34+ cells and whether daratumumab-related complement-dependent cytotoxicity (CDC) occurred. We also examined CD34+ cell progenitor cell colony capacity in assays with pre-plating incubation of CD34+ cells with daratumumab alone or with daratumumab and the CD59 inhibitory antibody BRIC229, and also assessed CD34+ cell responses to increasing doses of daratumumab in caspase 3/7 activity assays.

      Results

      Although 75% of mobilized CD34+ cells co-express CD38, CD38 was minimally present on CD34+ cells compared to Daudi and KG-1 controls, C1q did not bind to daratumumab-coated CD34+ cells, and CDC did not occur. CD34+ cells incubated in complement-rich human serum with daratumumab alone or with daratumumab and BRIC229, and then plated in progenitor cell assays, produced similar numbers of colonies as controls. In progenitor cell assays with cryopreserved or fresh unselected or CD34-selected cells, daratumumab did not affect progenitor cell capacity, and in caspase 3/7 activity assays CD34+ cells were not affected by increasing doses of daratumumab.

      Conclusion

      In vitro, daratumumab is not toxic to mobilized CD34+ progenitor cells from myeloma patients.
        Cover page: Daratumumab binds to mobilized CD34+ cells of myeloma patients in vitro without cytotoxicity or impaired progenitor cell growthCreative Commons 'BY' version 4.0 license
        • Article
        • Peer Reviewed
        UC Irvine Previously Published Works (2012)
        BACKGROUND

        In the setting of allogeneic stem cell transplantation (alloSCT), infusing natural killer (NK) cells from a major histocompatibility complex (MHC) mismatched donor can mediate an anti-leukemic effect. Graft versus tumor (GvT) effect following autologous stem cell transplantation (ASCT) may result in less disease relapse.

        STUDY DESIGN AND METHODS

        We performed a phase I clinical trial to assess the safety and feasibility of infusing distantly processed donor NK enriched mononuclear cell (NK-MC) infusions from a MHC haplotype mismatched (haploidentical) donor to patients who recently underwent ASCT for a hematologic malignancy. On day 1, peripheral blood mononuclear cells (MC) were obtained by steady-state leukapheresis and sent from Boston to the Production Assistance for Cellular Therapies (PACT) facility at the University of Minnesota, where immunomagnetic depletion of CD3 cells was performed on day 2. NK-MC product were then returned to Boston on day 2 for infusion on day 3. Toxicity, cellular product characteristics and logistic events were monitored.

        RESULTS

        At a median of 90 days (range, 49–191) following ASCT, thirteen patients were treated with escalating doses of NK-MC per kg from 105 to 2 ×107. Adverse effects included grade 2 rigors and muscle aches, but no grade 3 or 4 events, and no GvHD or marrow suppression. One air courier delay occurred. NK-MC products were viable with cytotoxic activity after transport.

        CONCLUSION

        CD3-depleted, MHC mismatched allogeneic NK-MC infusions can be safely and feasibly administered to patients after ASCT following distant processing and transport, justifying further development of this approach.

          Cover page: Autologous Stem Cell Transplant Recipients Tolerate Haploidentical Related-Donor Natural Killer Cell Enriched Infusions
          Top