LINE-1 methylation in plasma DNA as a biomarker of activity of DNA methylation inhibitors in patients with solid tumors.
Multiple clinical trials are investigating the use of the DNA methylation inhibitors azacitidine and decitabine for the treatment of solid tumors. Clinical trials in hematological malignancies have shown that optimal activity does not occur at their maximum tolerated doses but selection of an optimal biological dose and schedule for use in solid tumor patients is hampered by the difficulty of obtaining tumor tissue to measure their activity. Here we investigate the feasibility of using plasma DNA to measure the demethylating activity of the DNA methylation inhibitors in patients with solid tumors. We compared four methods to measure LINE-1 and MAGE-A1 promoter methylation in T24 and HCT116 cancer cells treated with decitabine treatment and selected Pyrosequencing for its greater reproducibility and higher signal to noise ratio. We then obtained DNA from plasma, peripheral blood mononuclear cells, buccal mucosa cells and saliva from ten patients with metastatic solid tumors at two different time points, without any intervening treatment. DNA methylation measurements were not significantly different between time point 1 and time point 2 in patient samples. We conclude that measurement of LINE-1 methylation in DNA extracted from the plasma of patients with advanced solid tumors, using Pyrosequencing, is feasible and has low within patient variability. Ongoing studies will determine whether changes in LINE-1 methylation in plasma DNA occur as a result of treatment with DNA methylation inhibitors and parallel changes in tumor tissue DNA.
Department of Genitourinary Medical Oncology, University of Texas, MD Anderson Cancer Center, Houston, TX 77030, USA. aaparicio@mdanderson.org
Ana
A
Aparicio
Brittany
B
North
Lindsey
L
Barske
Xuemei
X
Wang
Valentina
V
Bollati
Daniel
D
Weisenberger
Christine
C
Yoo
Nizar
N
Tannir
Erin
E
Horne
Susan
S
Groshen
Peter
P
Jones
Allen
A
Yang
Jean-Pierre
JP
Issa
D000951:Antigens, Neoplasm / Q000235:genetics; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology*; D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D014408:Biomarkers, Tumor / Q000235:genetics*; D045744:Cell Line, Tumor; D002610:Cheek; D019175:DNA Methylation / Q000187:drug effects*; D015254:DNA Modification Methylases / Q000037:antagonists & inhibitors*; D004273:DNA, Neoplasm / Q000097:blood / Q000378:metabolism*; D000077209:Decitabine; D006801:Humans; D020084:Long Interspersed Nucleotide Elements; D058950:Melanoma-Specific Antigens; D009061:Mouth Mucosa / Q000378:metabolism; D009363:Neoplasm Proteins / Q000235:genetics; D009369:Neoplasms / Q000097:blood / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D012463:Saliva / Q000378:metabolism; D017422:Sequence Analysis, DNA
D000951:Antigens, Neoplasm; D000964:Antimetabolites, Antineoplastic; D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; C072011:MAGEA1 protein, human; D058950:Melanoma-Specific Antigens; D009363:Neoplasm Proteins; D000077209:Decitabine; D015254:DNA Modification Methylases; D001374:Azacitidine