beta-lapachone, a novel plant product, overcomes drug resistance in human multiple myeloma cells.
OBJECTIVE
To evaluate the anti-tumor potential of beta-lapachone in multiple myeloma (MM) cell lines (U266, RPMI8226, and MM.1S); MM cell lines resistant to dexamethasone (MM.1R), melphalan (RPMI8226/LR5), doxorubicin (RPMI8226/DOX40), and mitoxantrone (RPMI8226/ MR20); and MM cells from patients (MM1-MM4).


METHODS
Cytotoxicity of beta-lapachone was assessed by MTT and [3H]-thymidine uptake assays. Apoptosis was analyzed using propidium iodide staining, DNA fragmentation, TUNEL assay, caspase-9 colorimetric assay, and immunoblotting for caspase-3, poly (ADP-ribose) polymerase (PARP), and caspase-8 cleavage products. Paracrine growth of MM cells was assessed by [3H]-thymidine uptake in cultures of bone marrow stromal cells (BMSCs) and MM cells. Interleukin-6 (IL-6) and vascular endothelial growth factor (VEGF) secretion in the culture supernatants was measured by specific enzyme-linked immunosorbent assays (ELISAs).


RESULTS
beta-lapachone showed significant cytotoxicity in MM cells (IC(50): 4-8 microM). In contrast, normal peripheral blood mononuclear cells (PBMCs) and BMSCs from MM patients were relatively resistant (IC(50): 8-16 microM). IL-6 did not protect against beta-lapachone-induced apoptosis in MM.1S cells, and dexamethasone showed additive cytotoxicity. beta-lapachone also decreased binding of MM.1S cells to BMSCs; abrogated IL-6 and VEGF secretion triggered by adhesion of BMSCs to MM.1S cells; reduced proliferation of MM.1S cells adherent to BMSCs; and decreased intracellular adhesion molecule-1 (ICAM-1) expression on MM.1S cells. Furthermore, beta-lapachone induced typical PARP cleavage, increased caspase-9 proteolytic activity, and activation of caspase-3, without activation of caspase-8 in U266 cells.


CONCLUSIONS
These studies provide a framework for clinical evaluation of beta-lapachone to improve the outcome for patients with MM.
Gupta
Deepak
D
Jerome Lipper Myeloma Center, Department of Adult Oncology, Dana Farber Cancer Institute, Boston, MA 02115, USA.
Podar
Klaus
K
Tai
Yu Tzu
YT
Lin
Boris
B
Hideshima
Teru
T
Akiyama
Masaharu
M
LeBlanc
Richard
R
Catley
Laurence
L
Mitsiades
Nicholas
N
Mitsiades
Constantine
C
Chauhan
Dharminder
D
Munshi
Nikhil C
NC
Anderson
Kenneth C
KC
D000903:Antibiotics, Antineoplastic / Q000494:pharmacology*; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects; D020169:Caspases / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D003907:Dexamethasone / Q000494:pharmacology; D004317:Doxorubicin / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm; D004354:Drug Screening Assays, Antitumor; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D004792:Enzyme Precursors / Q000378:metabolism; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis / Q000235:genetics; D015850:Interleukin-6 / Q000494:pharmacology; D007963:Leukocytes, Mononuclear / Q000187:drug effects; D008558:Melphalan / Q000494:pharmacology; D008942:Mitoxantrone / Q000494:pharmacology; D009101:Multiple Myeloma / Q000473:pathology*; D009285:Naphthoquinones / Q000494:pharmacology*; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics; D019899:Paracrine Communication; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D017154:Stromal Cells / Q000166:cytology / Q000187:drug effects; D059004:Topoisomerase I Inhibitors; D059005:Topoisomerase II Inhibitors; D014407:Tumor Cells, Cultured / Q000187:drug effects
D000903:Antibiotics, Antineoplastic; D000972:Antineoplastic Agents, Phytogenic; D004791:Enzyme Inhibitors; D004792:Enzyme Precursors; D015850:Interleukin-6; D009285:Naphthoquinones; D009363:Neoplasm Proteins; D059004:Topoisomerase I Inhibitors; D059005:Topoisomerase II Inhibitors; D018799:Intercellular Adhesion Molecule-1; C014638:beta-lapachone; D003907:Dexamethasone; D004317:Doxorubicin; D008942:Mitoxantrone; D011065:Poly(ADP-ribose) Polymerases; D020169:Caspases; D008558:Melphalan