Benzethonium chloride: a novel anticancer agent identified by using a cell-based small-molecule screen.
OBJECTIVE
This study aims to identify a novel therapeutic agent for head and neck cancer and to evaluate its antitumor efficacy.


METHODS
A cell-based and phenotype-driven high-throughput screening of approximately 2,400 biologically active or clinically used compounds was done using a tetrazolium-based assay on FaDu (hypopharyngeal squamous cancer) and NIH 3T3 (untransformed mouse embryonic fibroblast) cells, with secondary screening done on C666-1 (nasopharyngeal cancer) and GM05757 (primary normal human fibroblast) lines. The "hit" compound was assayed for efficacy in combination with standard therapeutics on a panel of human cancer cell lines. Furthermore, its mode of action (using transmission electron microscopy and flow cytometry) and its in vivo efficacy (using xenograft models) were evaluated.


RESULTS
Benzethonium chloride was identified as a novel cancer-specific compound. For benzethonium (48-hour incubation), the dose required to reduce cell viability by 50% was 3.8 micromol/L in FaDu, 42.2 micromol/L in NIH 3T3, 5.3 micromol/L in C666-1, and 17.0 micromol/L in GM05757. In vitro, this compound did not interfere with the effects of cisplatin, 5-fluorouracil, or gamma-irradiation. Benzethonium chloride induced apoptosis and activated caspases after 12 hours. Loss of mitochondrial membrane potential (DeltaPsiM) preceded cytosolic Ca2+ increase and cell death. In vivo, benzethonium chloride ablated the tumor-forming ability of FaDu cells, delayed the growth of xenograft tumors, and combined additively with local tumor radiation therapy. Evaluation of benzethonium chloride on the National Cancer Institute/NIH Developmental Therapeutics Program 60 human cancer cell lines revealed broad-range antitumor activity.


CONCLUSIONS
This high-throughput screening identified a novel antimicrobial compound with significant broad-spectrum anticancer activity.
Yip
Kenneth W
KW
Department of Medical Biophysics, University of Toronto, and Department of Medical Oncology, Princess Margaret Hospital, University Health Network, Toronto, Ontario, Canada.
Mao
Xinliang
X
Au
P Y Billie
PY
Hedley
David W
DW
Chow
Sue
S
Dalili
Shadi
S
Mocanu
Joseph D
JD
Bastianutto
Carlo
C
Schimmer
Aaron
A
Liu
Fei-Fei
FF
D000818:Animals; D000970:Antineoplastic Agents / Q000302:isolation & purification* / Q000494:pharmacology / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects; D001558:Benzethonium / Q000302:isolation & purification* / Q000494:pharmacology / Q000627:therapeutic use; D002118:Calcium / Q000378:metabolism; D020169:Caspases / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects / Q000528:radiation effects; D002470:Cell Survival / Q000187:drug effects; D004354:Drug Screening Assays, Antitumor / Q000379:methods*; D004359:Drug Therapy, Combination; D005260:Female; D006258:Head and Neck Neoplasms / Q000188:drug therapy / Q000532:radiotherapy; D006801:Humans; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D008807:Mice, Inbred BALB C; D016513:Mice, SCID; D051336:Mitochondrial Membranes / Q000187:drug effects; D008954:Models, Biological; D041681:NIH 3T3 Cells; D009369:Neoplasms / Q000188:drug therapy / Q000532:radiotherapy; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology / Q000627:therapeutic use; D046888:Tissue Array Analysis / Q000379:methods*; D014407:Tumor Cells, Cultured; D023041:Xenograft Model Antitumor Assays / Q000379:methods
D000970:Antineoplastic Agents; D011838:Radiation-Sensitizing Agents; D001558:Benzethonium; D020169:Caspases; D002118:Calcium