Combined TP53 mutation/3p loss correlates with decreased radiosensitivity and increased matrix-metalloproteinase activity in head and neck carcinoma.
OBJECTIVE
Patients with head and neck squamous cell carcinoma (HNSCC) containing TP53 mutation and 3p deletion ("double-hit") have poorer prognosis compared to patients with either event alone ("single-hit"). The etiology for worse clinical outcomes in patients with "double-hit" cancers is unclear. We compared radiosensitivity of cell lines containing both TP53 mutations and deletion of Fragile Histidine Triad (FHIT, the gene most commonly associated with 3p deletion) to "single-hit" lines with only TP53 mutation. We compared radiosensitivity in a "single-hit" cell line with TP53 mutation converted to "double-hit" using RNA interference targeting FHIT. Finally, we compared matrixmetalloproteinase-2/9 (MMP-2/9) activity, a previously-established biomarker for tumor aggressiveness, in xenograft tumors derived from these cell lines.


METHODS
TP53 mutation and FHIT deletion profiles of HNSCC lines were established using Cancer Cell Line Encyclopedia (CCLE). We used RNA-interference to convert a "single-hit" cell line (SCC4) to "double-hit". Cultured cells were examined for radiosensitivity and cisplatin sensitivity. MMP-2/9 activity was evaluated in "double-hit" versus "single-hit" tumors using ratiometric activatable cell-penetrating peptide (RACPP) in tongue (n=17) and flank xenografts (n=4).


RESULTS
Radiotherapy caused greater double-stranded DNA breaks in "single-hit" vs naturally occurring and engineered "double-hit" cells. In-vivo, "double-hit" xenografts demonstrated higher MMP-2/9 activity compared to "single-hit" xenografts (p<0.01). There was no difference in cisplatin sensitivity between the cell lines.


CONCLUSIONS
TP53 mutation combined with FHIT deletion correlates with decreased radiosensitivity in HNC cell lines. Xenograft from "double-hit" cells exhibit increased MMP-2/9 activity. These findings may in part account for the worse clinical outcome seen in patients with HNSCC "double-hit" tumors.
Division of Head and Neck Surgery, University of California, San Diego, CA, USA.
Sharat C
SC
Raju
Division of Head and Neck Surgery, University of California, San Diego, CA, USA.
Samantha J
SJ
Hauff
Division of Head and Neck Surgery, University of California, San Diego, CA, USA.
Aaron J
AJ
Lemieux
Division of Head and Neck Surgery, University of California, San Diego, CA, USA.
Ryan K
RK
Orosco
Bioinfomatics and Systems Biology, University of California, San Diego, CA, USA.
Andrew M
AM
Gross
Division of Head and Neck Surgery, University of California, San Diego, CA, USA.
Linda T
LT
Nguyen
Department of Pharmacology, University of California, San Diego, CA, USA.
Elamprakash
E
Savariar
Division of Head and Neck Surgery, University of California, San Diego, CA, USA.
William
W
Moss
Department of Pharmacology, University of California, San Diego, CA, USA.
Michael
M
Whitney
Moores Cancer Center, San Diego, CA, USA.
Ezra E
EE
Cohen
Moores Cancer Center, San Diego, CA, USA.
Scott M
SM
Lippman
Department of Pharmacology, University of California, San Diego, CA, USA; Howard Hughes Medical Institute, San Diego, CA, USA.
Roger Y
RY
Tsien
Bioinfomatics and Systems Biology, University of California, San Diego, CA, USA; Division of Medical Genetics, University of California, San Diego, CA, USA.
Trey
T
Ideker
Department of Radiation Medicine and Applied Sciences, University of California, San Diego, CA, USA.
Sunil J
SJ
Advani
Division of Head and Neck Surgery, University of California, San Diego, CA, USA; Department of Pharmacology, University of California, San Diego, CA, USA; Moores Cancer Center, San Diego, CA, USA. Electronic address: q1nguyen@ucsd.edu.
Quyen T
QT
Nguyen
D017766:Acid Anhydride Hydrolases / Q000235:genetics; D002294:Carcinoma, Squamous Cell / Q000201:enzymology / Q000235:genetics* / Q000532:radiotherapy; D045744:Cell Line, Tumor; D002872:Chromosome Deletion; D002893:Chromosomes, Human, Pair 3; D016158:Genes, p53; D006258:Head and Neck Neoplasms / Q000201:enzymology / Q000235:genetics* / Q000532:radiotherapy; D006801:Humans; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D009154:Mutation; D009363:Neoplasm Proteins / Q000235:genetics; D011836:Radiation Tolerance; D000099170:Bis(5'-adenosyl)triphosphatase
D017766:Acid Anhydride Hydrolases; D020782:Matrix Metalloproteinases; D009363:Neoplasm Proteins; D000099170:Bis(5'-adenosyl)triphosphatase
3p Deletion; Double-stranded DNA breaks; FHIT; Head and neck cancer; Matrix metalloproteinases; RNA interference; Radiosensitivity; TP53 mutation; “double-hit”; “single-hit”