Apoptosis, 5-fluorouracil sensitivity and expression of apoptotic proteins in a human ectocervical cell carcinogenesis model using different media.
Apoptosis has received widespread attention for its essential roles in biology, medicine and cancer. We previously found that normal, human papillomavirus (HPV) 16-immortalized and their transformed endocervical cells were increasingly resistant to apoptosis induced by a cancer therapeutic drug. Here, analogously, another common anticancer drug, 5-fluorouracil, in an ectocervical cell carcinogenesis model induced apoptosis in primary human ectocervical cells (HEC), whereas HPV18-immortalized HEC (HEC-18) and transformed HEC-18 (HEC-18T) were more resistant. Growth in serum/low density lipoprotein (LDL)-containing medium reversed resistance to 5-fluorouracil-induced apoptosis, particularly in HEC-18T. Cell viability results confirmed these findings. Using Western blots to compare protein levels with those of HEC not treated with 5-fluorouracil, the fold changes in HEC-18 and HEC-18T in LDL-free medium were 1.6-6.1-fold lower for pro-apoptotic p53, Bak and Bax. Four anti-apoptotic proteins were altered -2.1 to+14.6-fold for Bcl-2 and BAG-1 isoform p33 and p29. For BAG-1 p50 and p46, HEC-18 were weakly expressed and HEC-18T were moderately higher. Grown in LDL-containing medium, the differences in pro-apoptotic protein levels were mostly reversed. Expression was 1.4-32-fold higher in HEC-18 and HEC-18T of p53, Bax, BAG-1 p29, BAG-1 p33 and total BAG-1. These results showed that HEC carcinogenesis results in resistance to 5-fluorouracil-induced apoptosis, associated with reduced expression during carcinogenesis of pro-apoptotic proteins and increased expression of specific anti-apoptotic proteins.
Mo
Bilan
B
Division of Basic Medical Sciences, Faculty of Medicine, Memorial University of Newfoundland, 300 Prince Philip Drive, St. John's, Newfoundland, Canada A1B 3V6.
Pater
Alan
A
D000230:Adenocarcinoma / Q000378:metabolism* / Q000473:pathology; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D002461:Cell Line, Transformed; D002470:Cell Survival / Q000187:drug effects; D016895:Culture Media, Serum-Free; D019008:Drug Resistance, Neoplasm; D005260:Female; D005472:Fluorouracil / Q000494:pharmacology*; D006801:Humans; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D014407:Tumor Cells, Cultured; D002583:Uterine Cervical Neoplasms / Q000378:metabolism* / Q000473:pathology
D000964:Antimetabolites, Antineoplastic; D016895:Culture Media, Serum-Free; D011518:Proto-Oncogene Proteins; D005472:Fluorouracil