Enhanced radiosensitization and chemosensitization in NF-kappaB-suppressed human oral cancer cells via the inhibition of gamma-irradiation- and 5-FU-induced production of IL-6 and IL-8.
We examined the mechanisms underlying the enhancement of radiosensitivity and chemosensitivity to gamma-irradiation (IR) and 5-Fluorouracil (5-FU) in human oral carcinoma cells (B88) in which NF-kappaB activity was constitutively suppressed. Three super-repressor form of IkappaBalpha cDNA-transfected cell (B88mI) clones and 1 empty vector-transfected cell clone (B88neo) have been established. We found that the tumor-forming ability in nude mice of B88mI clones was significantly lower than that of B88 or B88neo. This suppressed ability in tumorigenicity was attributed to the down-regulation of the expression of interleukin (IL)-1alpha, IL-6, IL-8, vascular endothelial growth factor (VEGF) and matrix metalloproteinase (MMP)-9 in B88mI cell clones as compared to that in B88 or B88neo. IR and 5-FU induced a much greater degree of apoptosis, as evidenced by flow cytometry analysis and annexin V staining, in B88mI cell clones than in B88 or B88neo. When tumor-bearing nude mice were treated with IR or 5-FU, the suppression of tumor growth was significantly augmented in B88mI cell clones as compared to that in B88 or B88neo. ELISA analysis indicated that although a remarkable increase in production of IL-6 and IL-8 was observed in B88 and B88neo after in vitro exposure to IR or treatment with 5-FU, radiotherapy and chemotherapy-induced production of these cytokines was significantly suppressed in B88mI cell clones. These findings suggest that production of angiogenic factors and growth factors in response to radiotherapy and chemotherapy is a principal mechanism of inducible radioresistance and chemoresistance in human oral cancers, and establish the inhibition of NF-kappaB as a rational approach to improve conventional radiotherapy and chemotherapy outcomes.
Tamatani
Tetsuya
T
Second Department of Oral and Maxillofacial Surgery and Oncology, Tokushima University School of Dentistry, 1 Kuramoto-cho, Tokushima 770-8504, Japan.
Azuma
Masayuki
M
Ashida
Yuki
Y
Motegi
Katsumi
K
Takashima
Rina
R
Harada
Koji
K
Kawaguchi
Shin-ichi
S
Sato
Mitsunobu
M
D000818:Animals; D017304:Annexin A5 / Q000494:pharmacology; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology*; D017209:Apoptosis; D015153:Blotting, Western; D002277:Carcinoma / Q000188:drug therapy / Q000532:radiotherapy; D002455:Cell Division; D002467:Cell Nucleus / Q000378:metabolism; D002469:Cell Separation; D017077:Culture Media, Conditioned / Q000494:pharmacology; D003600:Cytosol / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D005472:Fluorouracil / Q000494:pharmacology*; D005720:Gamma Rays; D005822:Genetic Vectors; D006801:Humans; D020672:I-kappa B Proteins / Q000378:metabolism; D007150:Immunohistochemistry; D015850:Interleukin-6 / Q000096:biosynthesis*; D016209:Interleukin-8 / Q000096:biosynthesis*; D008156:Luciferases / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D051379:Mice; D008819:Mice, Nude; D009062:Mouth Neoplasms / Q000188:drug therapy* / Q000378:metabolism* / Q000532:radiotherapy*; D009154:Mutation; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism*; D009389:Neovascularization, Pathologic; D009841:Oligonucleotides / Q000494:pharmacology; D013997:Time Factors; D014162:Transfection; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
D017304:Annexin A5; D000964:Antimetabolites, Antineoplastic; D017077:Culture Media, Conditioned; D018076:DNA, Complementary; D020672:I-kappa B Proteins; D015850:Interleukin-6; D016209:Interleukin-8; D016328:NF-kappa B; C000606204:NFKBIA protein, human; C000606205:Nfkbia protein, mouse; D009841:Oligonucleotides; D042461:Vascular Endothelial Growth Factor A; D000072000:NF-KappaB Inhibitor alpha; D008156:Luciferases; D020780:Matrix Metalloproteinase 9; D005472:Fluorouracil