title: Human squamous cell carcinoma of the tongue and colon undergoes apoptosis upon phagocytosis of Saccharomyces cerevisiae, the baker's yeast, in vitro.
abstract: The present study was carried out to evaluate the effect of phagocytosis of killed yeast on the induction of apoptosis in two human solid tumors of the gastrointestinal (GI): the squamous cell carcinomas of the tongue (SCCA) are (SCC-4 and SCC-9) and the adenocarcinomas of the colon (ADENOCA) are (Caco-2 and DLD-1). Cancer cells were cultured with heat killed Saccharomyces cerevisiae, baker's and brewer's yeast, at ratio of yeast to cancer cells = 10:1. The percentage of tumor cells that had attached/phagocytosed yeast and oxidative burst was determined by using oxidative sensitive dye (DCFH-DA) and flow cytometry. SCC-4 and colon Caco-2 cells demonstrated initial high levels of phagocytosis that peaked (35.8-52.8%) at 2 hr. The oral SCC-9 and colon DLD-1 cells demonstrated low phagocytic activity (7-12%). Phagocytosis was not associated with oxidative burst. Upon phagocytosis of yeast, cancer cells underwent apoptosis that was maximized at 4 hr. Yeast-induced apoptosis was significant in SCC-4 (45%), as compared with SCC-9 cells (17%), and Caco-2 (76%), as compared with DLD cells (12%). Apoptosis in cancer cells was inhibited by caspase inhibitor, Z-VAD-FMK; this suggests that caspases may be involved in apoptosis of the GI cancers. This data may have clinical implications for the treatment of solid tumors.
authors.affiliation: Drew University of Medicine and Science, Department of Otolaryngology, 1621 E. 120th Street, Los Angeles, CA 90059, USA. mghoneum@ucla.edu
authors.forename: Mamdooh
authors.initials: M
authors.lastname: Ghoneum
authors.forename: Jason
authors.initials: J
authors.lastname: Hamilton
authors.forename: Jimmy
authors.initials: J
authors.lastname: Brown
authors.forename: Sastry
authors.initials: S
authors.lastname: Gollapudi
mesh_terms: D000230:Adenocarcinoma / Q000382:microbiology* / Q000473:pathology / Q000628:therapy; D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D017209:Apoptosis / Q000502:physiology*; D018938:Caco-2 Cells; D002294:Carcinoma, Squamous Cell / Q000382:microbiology* / Q000473:pathology / Q000628:therapy; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms / Q000382:microbiology* / Q000473:pathology / Q000628:therapy; D006801:Humans; D010587:Phagocytosis; D012441:Saccharomyces cerevisiae; D014062:Tongue Neoplasms / Q000382:microbiology* / Q000473:pathology / Q000628:therapy; D020298:U937 Cells
chemical_list: D000590:Amino Acid Chloromethyl Ketones; D061945:Caspase Inhibitors; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D020169:Caspases