Potentiating Effect of the Flavonolignan (‐)‐Hydnocarpin in Combination with Vincristine in a Sensitive and P‐gp‐Expressing Acute Lymphoblastic Leukemia Cell Line

Abstract

The potentiating action of the flavonolignan, (-)-hydnocarpin, in combination with vincristine was evaluated in the 697 acute lymphoblastic leukemia cell line and a P-gp-expressing variant, 697-R. Vincristine at 3 nM caused nearly complete growth inhibition in 697 cells, versus a 17% growth inhibition in 697-R cells. When combined with (-)-hydnocarpin at concentrations of 10 and 5 µM, vincristine-mediated growth inhibition in the 697-R cells increased significantly over the sum of the individual agents to 72% (p ≤ 0.0001), and 41% (p = 0.0256), respectively. Vincristine at 1.5 nM (66% growth inhibition) and 0.75 nM (39% growth inhibition) combined with (-)-hydnocarpin at 10 µM (42% growth inhibition) in the 697 cells, caused a significant increase in growth inhibition to 83% (p = 0.03) and to 61% (p < 0.0001), respectively, when compared to vincristine treatment as a single agent. To investigate the mechanism for the vincristine re-sensitization caused by (-)-hydnocarpin, the P-gp inhibitory effect of (-)-hydnocarpin was evaluated.

Bioactive Constituents of Indigofera spicata

“…The 697 and Raji cell lines were cultured as previously described. 46 The 697 pre-B acute lymphoblastic leukemia cell line was obtained from Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH (DSMZ) (Braunschweig, Germany), and the Raji human Burkitt’s lymphoma was obtained from the American Type Culture Collection (ATCC) (Manassas, VA, USA). The density of 697 and Raji cells was adjusted to 200,000 cells/mL.…”

“…The MTS experiment was performed as previously described. 46 For the PI experiment, cells (95 µL/well), test compounds (5 µL/well), and vincristine (25 and 5 nM), were placed in eight wells (one column) of a 96-well microplate, and incubated for 48 and 72 h. After the incubation period, each test sample was mixed by re-suspension and transferred to flow tubes, then centrifuged at 1200 rpm for 6 min. Supernatant was decanted and the pellet re-suspended in 200 µL of the PI/PBS solution, consisting of 50 µL of PI and 2.0 mL of PBS.…”

Discovery of Anticancer Agents of Diverse Natural Origin

“…A key aspect of our group interactions is the prioritization of in vitro- active crude extracts for subsequent activity-guided purification (17, 18). Cytotoxicity assays using selected cancer cell lines are conducted currently mainly at our biological testing core component at UlC [for example, see (54–56)], with some solid tumor and leukemia cancer cell line testing also having been carried out at OSU [for example, see (54, 57, 58)]. Selected target-based in vitro bioassays that have been conducted for the program project include activation of nuclear factor κB (NFκB) (56, 59), mitochondrial transmembrane potential (MTP) (60), and semaphorin 3B assays (61).…”

Unconventional application of the Mitsunobu reaction: Selective flavonolignan dehydration yielding hydnocarpins

“…Combination of these antibiotics together with hydnocarpin (MDR inhibitor) helped to treat such a persistent disease like leprosy caused by M. leprae . Recently, hydnocarpin (isolated from Brucea javanica ; which was named as (−)-hydnocarpin, even though the enantiomeric purity was not determined) has been described as potentiator of vincristine’s cytotoxicity due to MDR inhibition [ 18 ]. Furthermore, 5-methoxyhydnocarpin has been described to enhance the antimicrobial activity of berberine [ 19 ].…”