Toxicity mechanisms of amphotericin B and its neutralization by conjugation with arabinogalactan.
Amphotericin B (AMB) is an effective antifungal agent. However, its therapeutic use is hampered by its toxicity, mainly due to channel formation across kidney cell membranes and the disruption of postendocytic trafficking. We previously described a safe injectable AMB-arabinogalactan (AG) conjugate with neutralized toxicity. Here we studied the mechanism of the toxicity of free AMB and its neutralization by conjugation with AG. AMB treatment of a kidney cell line modulated the trafficking of three receptors (C-X-C chemokine receptor type 4 [CXCR4], M1 receptor, and human transferrin receptor [hTfnR]) due to an increase in endosomal pH. Similar data were also obtained in yeast but with an increase in vacuolar pH and the perturbation of Hxt2-green fluorescent protein (GFP) trafficking. The conjugation of AMB with AG neutralized all elements of the toxic activity of AMB in mammalian but not in fungal cells. Based on these results, we provide an explanation of how the conjugation of AMB with AG neutralizes its toxicity in mammalian cells and add to the knowledge of the mechanism of action of free AMB in both fungal and mammalian cells.
Department of Clinical Microbiology and Infectious Diseases, Hadassah-Hebrew University Medical Center, Jerusalem, Israel.
Sarah
S
Kagan
Diana
D
Ickowicz
Miriam
M
Shmuel
Yoram
Y
Altschuler
Edward
E
Sionov
Miriam
M
Pitusi
Aryeh
A
Weiss
Shimon
S
Farber
Abraham J
AJ
Domb
Itzhack
I
Polacheck
D000666:Amphotericin B / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D000935:Antifungal Agents / Q000737:chemistry / Q000494:pharmacology*; D002176:Candida albicans / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D019743:Chemokines, CXC / Q000378:metabolism; D002522:Chlorocebus aethiops; D004285:Dogs; D011992:Endosomes / Q000187:drug effects / Q000378:metabolism; D005685:Galactans / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007668:Kidney / Q000166:cytology / Q000187:drug effects* / Q000382:microbiology; D061985:Madin Darby Canine Kidney Cells; D008826:Microbial Sensitivity Tests; D021381:Protein Transport / Q000187:drug effects; D043643:Receptor, Muscarinic M1 / Q000378:metabolism; D019718:Receptors, CXCR4 / Q000378:metabolism; D011990:Receptors, Transferrin / Q000378:metabolism; D013045:Species Specificity; D014168:Transferrin / Q000378:metabolism; D014709:Vero Cells
D000935:Antifungal Agents; D019743:Chemokines, CXC; D005685:Galactans; D043643:Receptor, Muscarinic M1; D019718:Receptors, CXCR4; D011990:Receptors, Transferrin; D014168:Transferrin; C492445:amphotericin B-arabinogalactan conjugate; D000666:Amphotericin B